The full test data, complete with methodology and screenshots, was sent to AskLibreOffice, and the initial signs - one false answer and only 35 views as at tonight - are not encouraging.
The major headline - the show-stopper - is that Calc cannot process linked workbooks reliably. It therefore cannot fill the shoes of Excel, leaving Excel as the only show in town. This kills off any possibility that Calc could have had to be a member of a cross-platform/multi-platform office environment (e.g. a bring-your-own-device 'open' corporate network), or a single-user transitional environment (e.g. migrating from Windows to Linux over time, to de-risk the migration process).
There is little else I can do but wait until either:
- LibreOffice has fixed the problem; or
- Linux Mint has swapped Calc in Mint's repository for something better/workable/functional; or
- Linux Mint has strongly pressured LibreOffice to fix Calc before Calc's lack of matching Excel's basic functionality becomes a derivative drag on the adoption of Linux Mint; or
- Microsoft buys out Linux Mint; or
- Microsoft vexatiously sues LibreOffice for intellectual property theft.
It is really important to emphasise that Linux Mint is a fantastic product. I've loved using it. Mint really deserves success and to grow its retail/non-tech/non-geek userbase. But, for me, without a usable spreadsheet package, my sole use for Linux Mint is web-browsing. And that is a really poor reward to the thousands of hours that Mint's developers have poured into developing a top-notch graphical user desktop environment.