Great idea. Downloaded it.

I think that the column that says "N+.5", "N+1", etc. should be labeled "reciprocity correction" rather than "contrast," since that's what it seems to refer to in this context. I'd also specify for clarity that the tables for "Tri-X Pan" are for "Tri-X 320," since some people may want to use this for Tri-X 400 as well, though I suspect the correction is for all intents and purposes the same.

Maybe a later version you could add in bellows factor, calculable by various methods, and filter factor, to produce a result with all the relevant components: base exposure + filter factor + bellows factor + reciprocity factor based on the sum of the first three elements.

Then the real bees knees would be a light meter with Zone system calculations plus all of the above.