I've been reading the V4 spec and noticed an issue with the V4 rate worksheet. For the ARQ modes, it appears you only included 1 T/R switch time in the Frame Cycle computation. Shouldn't there be two? That makes the net throughput numbers:
ASCII ARQ: 30.62/262.49/43.75
UTF-8 ARQ: 32.01/240.08/40.01
(bps, chr/min, wpm)
Also, in the ARQ Frame Timing Details diagram, Tdly is between 50 and 100 ms. If we assume that the decoder flush time (128 ms) overlaps with the T/R time, we still end up with a max of 228 ms between T and R according to the diagram. Also, since there is no flush at the end of the ARQ packet, that is even more of a discrepancy.
Sorry if these issues have already been addressed.