The restrictions you are quoting only apply to the LGC, the computer in the Lunar Module. The Command Module Computer does not have these restrictions (compare the section about the Coasting Integration Routine you quote with the same passage from the document about the CMC: https://www.ibiblio.org/apollo/Documents/R-577-Colossus2-Martin-5.2.pdf). The CMC ...
I think, though I'm not certain, that Wikipedia is in fact wrong in this situation, probably for the reason you just mentioned.
From this article, A square peg in a cone-shaped hole: The Samos E-5 recoverable satellite (part 2):
Herther had determined that a launch vehicle’s inertial measurement system’s gyroscopes would drift during the powered flight ...
According to the Apollo 14 LM Timeline Book, the MODE SEL switch that selects the source for the pointers is set at two different points.
At LANDING RADAR CHECKOUT, at mission time 106:30, the RATE ERR MON switch is set to LDG RDR/CMPTR and MODE SEL is set to LR, so the cross-pointers are controlled from the landing radar.
Between 108:00 and 108:20, we ...
Check out the FORTH language. It makes no distinction between user code and the code in the (tiny) OS kernel. It was used in the firmware of early satellites.
A good description is here: