Hold Down Command Key (AppleScript)

I'm trying to fix the following macro, which isn't working for some reason. When I hold down the keypad 1 key, I can see that the macro is being activated, but it doesn't act like command is being held down (e.g. if I hold key pad 1 and press t, a new tab should open, but it doesn't). Any suggestions?

Modifier down.kmmacros (3.2 KB)