.. the comment I referred to, earlier...,
but the example you showed me might well be "optimized" rather than calculated, eh?

-shrug-
I'd been thinking of defects, flaws, and other things that give Excel it's Look & Feel[tm], though, like the other comment ( wherever it is, I'm not going digging again ) .. about a query that took over 20 minutes on Excel, but a minute or so on Linux: oughtn't they too be duplicated, even if one has to set an option for 'em ( like Stupidly-Bad Slowness Option, and Compromising Data-Integrity Option )?...
hmmm..
I seem to remember another discussion, here on /., where someone had a problem with Excel: they personally had switched to Linux/OSS, on their desktop, and they did a spreadsheet in their system, and their boss had a different result, so they went over every last thing, and discovered that the Excel version was rong...

I don't use Excel, so I'm stuck with the choice of gnumeric ( SuSE 8.2 pro installed the "stable" version, and it was obnoxious enough in interface & habits that I didn't like it -- now that I know-about the "development" version being good-enough for beta, by gnome's coding-standards, I'm downloading it to try compiling/running it ), KSpread, and OO.o's spreadsheet ( I don't much care for OO.o, as it's a resource-hog, and takes a very long time to start on my 5-year old machine, even with 320MB/K6-2 )... KSpread seems a tad unfinished, so I simply chose to work on stuff not needing spreadsheets for a few months...

Now I need one, and gnumeric 1.1.x awaits, so I'll dig into it ta see if I dig it, see..

I find the reports about bugs in Excel's accuracy to be probable, though, because MS cannot possibly code by test-first ( and end-up with the results they do ) XP-style, and almost all of the Excel users don't check the results with a different spreadsheet to see if the results are correct ( who backups their system? who checks their tools' integrity? who verifies anything ), and since it isn't OSS, bugs are more likely to remain long-term ( the stunning amount of serious, been-there-for-years vulnerabilities in windoze... )

Knowing gnome's coding-integrity standards ( not necessarily caring for the gtk interface, though: QT's much nicer to work-with ), knowing OSS's more effective in destroying & eradicating bugs, I'm not going to trust my future to MS-Excel, when gnumeric is an option. Period.

( thanks and generally-emanated hugs, for all gnumeric & gnome developers, eh? we gain vastly from this all, and appreciate it, though sometimes our griping-habit overrules wisdom & wellbeing )