Most fixes only require localized changes in the sheet to get a small section to spit out the correct number or condition.
Large unit defense factor coming out to .9 was an example in the errata. V1.1 was attempting to use the units base TMM for that portion of the calculation. When its the total defense factor modifiers that needs to be taken into account.
Non jump capable infantry getting the jump bonus, needed an extra AND statement to see if the unit is both infantry and jumps. (plug in non jumping infantry from the MUL to test.)
Jump capable units and MAS interaction is based on the location of the +1 for jumping modifier as a movement modifier in the Defense factor modifiers table (Ground units) An example of this can be found on the
Purifier. Which is not being calculated correctly with V1.1
Industrial mechs getting offensive size. Rules state 'mechs get offensive size points. Correction was an OR statement checking to see if either a battlemech or an industrialmech was selected as the unit type.
Longer term problem, I think there is a hole in the defense factor rules. For the edge case of a jumping unit without weapons, that has a jumping movement split from its walking movement. For example 20/4j or 4/20j or 12/10j. I think I'll need more sleep, time to think, and probably an errata question to fix it. Fairly sure I went with the spirit of the rules in my own spreadsheet rather then the RAW.