While not perfect,
Just Knowing the convention used is how I dealt with this:
Note also, the numbers are ASCII when used in file names, so the leading 0 padding for single digits.
01.05 is a range, the 0x implies range
01.5 is a middle, between 1 and 2
10.12 is a range, just higher Note the decimal part is always treated as a integer AND it is larger, and yes, this falls apart if the number is a multiple of 10 (fairly rare. the giveaway is the initial integer is 9 or larger )
I use
0 for no sort position in a series/universe.
00.02 would be prequel numbering
And Yes, there are publishers that go out of their way to thwart me

with omnibus editions that SKIP items. 12 and 15, 07 and 09
Use EPUBsplit (the PI) and break them back into 2 books