A quick look at the code indicates to me that the Intel translator CONV86 may well have done the translation in "strict" mode. Of course, there were other translators, but some of the stuff rings a bell.
For example, the 8080 instruction INX B gets translated to SAHF INC BX LAHF all done because the 8080 16-bit instruction does not affect the zero and carry flags, but the 8086 instruction INC, does. So there's very likely a large amount (my experience was at least >30%) of cruft in the code. --Chuck