Calculations with max time format?

I'm in the process of creating an apeggiator (in m4l), and experiencing some problems with the length of the notes that are begin created. i have a metro (@active 1) that is running synced with live's main transport, at a speed that is selectable by the user (8n, 16n, etc). On every bang a note is created using makenote, which uses the same length-parameter (in max time format) for notelength.

This works, but when i send that midi-signal to my ms20 i think that either the time between the note-off and the next note-on is too small, or the note-off arrives slightly after the new note-on. Either way, my ms20 sees it as legato played notes and does not trigger a new envelope (only changing the pitch).

What i would like to do is adjust the selected time format for the makenote, make it shorter by a number of msecs. Something like: (selected time format) - 100ms.

Is there a way to do this?