Calculating cumulative ROI in MTTs?

So, I have a math question for all.
If you are tracking your ROI in MTTs, is the impact of a larger buy-in tournament higher than a micro-stakes?

In other words: I enter a $2.20 MTT and bust out. Then I enter a $0.10 SnG MTT and win $6. Is my ROI simply $6/(2.20 + 0.10) = 2.60 (260%)?

Overall ROI would be 100(6.00/2.30)-100 which is ~160%, you have to subtract your entry fees...yes, the impact of larger buyins is greater.

I know sharkscope uses avg ROI which would be almost 6000 in one and -100 in the other for almost 3000% avg, but that's just silly.

Yes, that`s right (with DW`s adjustment).

Simplest way is an Excel spreadsheet, entry fees in one column, wins in another. Set it up to calculate the ratio of the two column totals. Will do it in a flash, saves the brain strain.

Not sure how meaningful the result is, though. A single win in a decent tourney will make it look insanely good. Earnings per hour may be a more useful measure.