Welcome!
Did you get the Advantage or the newer Advantage2 ?
The Advantage has actually what is considered to be 6-key rollover. The 4 pairs of modifiers work with all other keys and the rollover number is counted as the smallest of all working possible key combinations, so the modifiers are not counted.
I.e. for x-KRO, there exists a combination of x + 1 keys, where the first x keys work together but not together with the one.
Why the Kinesis Advantage has precisely 6KRO, with the modifier keys treated separately is because it (like most other mechanical keyboards) is using a specific USB protocol that limits it to that - and because it is using that protocol is because it is known to have the least number of issues with different operating systems and BIOS:es.
Almost all keyboards are either 2-KRO, 6-KRO or N-KRO. Some keyboards are marketed as being 10-KRO or 14-KRO but those numbers are just including the modifiers (6+4 or 6+4×2) and not following the conventional definition.
My Kinesis Advantage does have a bug, however: If you hold 6 non-modifier keys and then press another non-modifier key, it will forget all of those keys. I have not heard that it has been fixed in another revision, but I have got confirmation that the Advantage2 does not have the bug.
