You would have been better asking this in your other thread since it is the same underlying question!
Limits are added in the order they are imported, so there is no way of knowing exactly what numbers will be applied, but you can look up the text of the level with:
lookup_from_id(id_limit, 'limitsort')
(see the 'Limit' stat)
That said, it is hard to check for text at the end of the string unless you know how long the string is.
You can use the "substring" function, but only in a column not a statistic.
See the
Custom Statistics and Reports FAQ for usage info - e.g. you could check for:
substring( lookup_from_id(id_limit, 'limitsort') from 7 for 7 ) = '(6 max)'
..but that will only work if the start of the string is the same length as your "$4 NL (6 max)" example.
I guess you could extend it to do:
substring( lookup_from_id(id_limit, 'limitsort') from 7 for 7 ) = '(6 max)' OR substring( lookup_from_id(id_limit, 'limitsort') from 8 for 7 ) = '(6 max)' OR ...