I am not a RM expert by any means but you may have to create a second rule with the trigger being the button released.
Triggers are exactly that, a trigger that causes the rule to be evaluated, so you need a button released trigger to stop the raise/lower.
Something you may want to consider. I use the same remotes for manual control of my window blinds. Instead of ramp up/down, I use the 2 & 3 buttons for incremental (10% each press) opening & closing. I use the community app Advanced Button Controller it makes this very easy to implement.
Mike
