Thank you @desertblade for the code. It works perfectly on my GE (Jasco) smart switches. For anyone who needs a quick primer on how to change the rate once the custom device handler is installed, this is what I did.
From the smartthings developer site (account.smartthings.com), change your switch device type to Enhanced Dimmer Switch.
Next, click edit under preferences and change:
Manual Size of Steps in Percent - Tap to set - Enter 99 as the value
Manual Steps Intervals Each 10 ms - Tap to set - Enter 3 as the value (2 probably works 2, I did 3 and it is now instant)
These two settings make it so that if you use the wall switches (i.e. manual) to turn on the lights, they jump instantly to their last brightness setting (if the last brightness setting was not 100%, it’ll jump immediately to whatever they were last on).
If you want the same behavior to occur when the lights are invoked via Alexa or some other non manual method, then change the steps & intervals in that part of the preferences config to the same numbers.
Click save when you are done changing numbers.
Then… the last step I did was from within the app on your phone, go to each devices page and click “Configure” – this seems to lock in the new setting for the switch.
At that point, you should be able to change them back to a standard dimmer switch and have the config hold.