Format Cells -> User Defined -> Conditional Brackets won't accept more than 2 conditional terms and 3 total terms

Trying to generate a format that will turn 1k block values into “human readable” values (2^10n style) based on size. I took what is apparently an Excel formula and tried to make it work in Calc. However, I want to include from TiB to MiB and finally KiB. Unfortunately, it seems that the conditional bracket notation still only allows up two three conditions, two defined and one default.

So for example, the format cells dialog will not accept this format string:

[>=1073741824]#.# “TB”;[>=1048576]#.# “GB”;[>=1024]#.# “MB”;General

but it does accept this one:

[>=1073741824]#.# “TB”;[>=1048576]#.# “GB”;#.# “MB”

It seems to reject a conditional bracket clause in the third segment and no fourth segment is allowed at all.

This is… nowhere made clear or stated anywhere at all. Using conditional brackets in the user-defined format shouldn’t be limited to the fact that the non-bracket formats default to positive,negative,zero. I would argue this is a bug, but it is at very least a big documentation gap.

In my opinion, the documentation is written in sufficient detail. But, of course, you can make suggestions for improving it.
Regarding the restrictions on the number of conditions in number format - conditional formatting can help here.