I've been parsing and re-emitting some AP214 files from the wild, and checking rendering in the IDA-Step viewer.

I believe IDA-step has correctly identified an error with the emission order of certain complex entities...

From the original (correct) file:
#1200=(

BOUNDED_SURFACE()
B_SPLINE_SURFACE(....)
...
)

After read in and spat out by STEPcode:
#1200=(

B_SPLINE_SURFACE(....)
B_*...
BOUNDED_SURFACE()
...
)

I don't have a copy of P21 to check the correctness, but I'd assume IDAstep (and Solidworks) got this correct.