/gmroll is the same as /roll, but whispers the result to the gm. /w gm is just like typing a message except it is sent to the gm. That's probably sounds like a bunch of tautologies, but I say that to say that there is as much difference between /gmroll and /w gm as there is between /roll and just typing something out. That second is a good question.. Probably not. Macro expansion happens at step 2, and Roll Query expansion is step 4: <a href="https://wiki.roll20.net/Dice_Reference#Order_of_Op" rel="nofollow">https://wiki.roll20.net/Dice_Reference#Order_of_Op</a>... There are lots of clever people around (looks at Silvyre and Scott C.) that might have some workarounds.