Femano's article is a pretty poor scenario of why the plugs are there. In negating them as being security devices, and relying on the so called 'service shaft' as being the only access to the upper levels, there would be no need for the ascending passage at all. Considering the subterranean chamber's passage was sealed up, and the 'service shaft' did not exist at the time of construction, the plugs do identify that access to the upper levels was through the ascending passage.
(The entrance of the 'service shaft' in the descending passage is particular in its placement, and not through originally being incorporated in the pyramid's planning, but rather as being directly below an intended goal. Following its directions, and the placement of the 'grotto', one can identify the intended goal as being two-fold: vertically align the entrance with a horizontal alignment of the 'grotto' and X marks the spot of one intention; and the breach into the GG is such, a breach, from below. The block it goes through would have been wholly removed if making the passage from above, as a complete stone would be used to hide it, rather than a smaller stone that identifies something amiss because of the join being made: compared to the opposite blocks, the joins do not match.)
Restoration works do identify that care and respect was given to the pyramid, but how can we be sure how much was done? There seems to be attention in places that one should consider - as in why plaster is above the granite leaf and in the grooves? - and yet the top step of the GG and the ceiling blocks in the passages either side of the antechamber were so destroyed and left so.
I agree that the portcullises were not the sole impediment to access the KC, and I do so because of the conditions of the blocks either side of the antechamber, and the top step. To identify a pulley system to raise and lower the portcullises also identifies that ropes ran across the top step, and the use of the pulley system many times wore away the top step...in a specific fashion that equates to the pattern depicted in early photos of the top step.
I admit I do not agree with you and the seed storage design for the pyramid, sorry about that, and as I have mentioned elsewhere, I do believe the entrance-glyph defines a truer reason for the pyramid, and it does so by including pyramids and the Sphinx-like form, and particular astral bodies in alignment.