When a blueprint is drawn by the architect he decides how accurate the project needs to be or he wants it to be, + plus or - minus the dimensions he deems appropriate to the project, + or - .0001 of an inch, + or - 1 inch, or 1 foot or whatever the case.
This decision is based on many factors,
1. From an economic stand point, you would not build a barn to the tolerances that you would build a piano, it would make no sense at all and be extremely expensive and laborious to do it, if you could even do it
2. The need for accuracy, how accurate does he need to be to create the project and achieve the desired results.
3. The abilities of the builders to adhere to the specifications, there is no logic to demand tolerances that are beyond the abilities of the builders, skills and tools.
4. If the project is built over a long period of time in stages do the earliest builders have more or less ability to adhere to the tolerances, like advancement or decline in skills or tools.
5. Has the original blueprint been strictly adhered to or have there been revisions or copies made that vary from the original.
These are some of the factors that should be considered when we talk about the accuracy of the project.
Using the blueprints the builders construct the design with the factors we pointed out.
After the the construction is complete a survey can then be done, this we can call an "as built blueprint" it is accurate to the degree of the surveyors abilities and tools are capable of achieving. So now we have taken into account the + or - factor of the survey or "as built blueprint".
From my experience and logic is, most construction projects vary to different degrees by the factors stated above but more than likely is a completely recognizable facsimile of the original blueprints design, although certain dimensions are not what was on the original print.
A key question here is what tools did, in our case here, the Egyptians use to lay out the Giza Complex. If we consider my particular theory we are talking about laying out a complex over one mile in diameter. If we accept that they used ropes to do this, there are measuring rope examples found and are treated with compounds to control the humidity, moisture expands the rope leading to inaccuracies. The tension on the rope is a factor and will vary its length also the longer the rope, the more inaccurate it would be. So if we go with the rope theory what kind or tolerances can we expect the builders to have achieved? This is a very important question and my guess would be probably not
exact tolerances, what do you think + or - ? Your guess is as good as mine.
Although we see very accurate dimensions on the Pyramid of Khufu, the accuracy seems to decline as the project proceeded. An example is the pyramid of Menkaure is not as finely built as Khufu. We can see rather easily that the the accuracy has declined but why? I suppose there are differing theories on that to, I really don't know the answer but it is obviously declining in accuracy.
Now let's go back to the "as built blueprint" the surveyors made. I believe it is accepted to be the most accurate survey done to date, the Giza Mapping Project led by Mark Lehner. It used the most accurate tools to measure and I trust very competent engineers and surveyors. That being said there are other surveys to consider and most all have discrepancies and more often than not disagree with each others findings, some as much as 9 feet that I am aware of, there might be larger ones. They all measured what was built and is a result of all the factors we have discussed. I think it is safe to assume that it did vary to a degree from the original blueprint, would you agree?
If a theory is proposed for the design that is logical and can be pieced together like a puzzle to form a coherent plan and purpose to the design it should be entertained as a possibility. The more points that connect logically the more weight it will give a particular theory. So let's take the measuring system here for example, there are differing opinions on the exact length of the Royal Cubit, it is generally given as 20.62 + or - .04 off the top of my head correct me if I'm wrong. The point I want to make is that any of the lengths of the Royal Cubit that are given, unless it is 20.61818 do not fit into a larger coherent mathematical equation that takes into account important factors such as the speed of light, length of a mile the length of the Great Year etc. You cannot use any other numbers for the Cubit and achieve mathematical precision with the rest of the units in the measuring system. So although many different scholars have given their + or - lengths for the cubit only one number in particular does fit into the mathematical equation and reconciles all important factors in the measuring system. The point is though 20.61818 is not given as the length of the Royal Cubit but falls within the + or - tolerances it would be foolish to discount the fact that it fits into a larger and logical equation or template.
So if the measurements given in the survey don't fit into a pattern or logical design it would be wise to consider the + or - errors in the survey. In the original design the architect most likely had a theme or specific ideas he is designing into the project that would follow certain patterns. If by evaluating the given dimension in the "as built blueprint" by the surveyors does not fit exactly into a pattern but when adjusted to the + or - factors we discussed, it makes complete logical sense it should be considered and more measurements checked to see if by slightly adjusting the dimensions you arrive at a logical and recognizable design or plan. As the saying goes if it looks like a duck its probably a duck despite their subtle differences. I am absolutely in no way discounting the surveyors data simply looking at the design as a whole complete scene, not just focusing in the micro data, you can easily find yourself arguing over a specific measurement and fail to see the bigger picture that fits a coherent and logical theme.
I hope I have made my point, I welcome any discussion or critiquing on this topic as it is very important to our discussion here.