You should easily be able to read an ADC in well under 100uS (subject to input capacitances). After reading eight inputs, that leaves you 49mS to do your calculations. Enough time for at least a full Continental Breakfast and a couple of Coffee's as well!

It's so simple to read ADC's directly and have total and complete control, that I find ADCIN quite unnescessary and if anything a hinderance. I think it's really included for the convenience of those who are afraid of accessing a PIC's internals directly.

Melanie