After running them side by side, I'm getting numbers close enough (other than BV2, about which I do not care) so as to not make any difference - in a setting where we have a lot of warship designs done under Battlespace rules, or no rules at all, I'll call 1% here or there differences in production shipyards.
Ill probably keep using the Excel Spreadsheet, cause I like the extra detail and ability to fiddle with fluffy stuff, data areas for manufacturers, etc. I was unclear when I said 'slow'... What I suppose I should have said is 'lots of places to fill stuff in/options', so while it doesnt update slow, it was a little hard to manage at first.