Limitation on Date Math expression

I try to find every first Tuesday of the month from 20h to 7 am Wednesday , I use the following expression:
from now/M+7d/w+43h to now-1M/M+7d/w+55h
(Tuesday, January 5 at 8:00 p.m. Wednesday, January 6 8:00)
=> it's ok.

but when I want to add a parameter , I have errors
For example:
now/M-1M+7d/w+43h =>KO Syntax error

and then, for example , I have to spend the days in hours for this example to work
now-1M/M+7d/w+55h =>OK
now-1M/M+7d/w+1d+31h =>KO Syntax error

Is there a limit which prevents to cumulate too setting in date math expression ?