What about:
You create a Global Number Variable called JumpVariable
then
On platform jump:
set JumpVariable = 0
On platform land:
- if JumpVariable = 0 set PlatformGravity to 10 for exemple & simulate jump & add + 1 to JumpVariable
- if JumpVariable = 1 set PlatformGravity to 30 & simulate jump & add + 1 to JumpVariable
- if JumpVariable = 2 set PlatformGravity to 50 & simulate jump & add + 1 to JumpVariable
- if JumpVariable = 3 set PlatformGravity to Normal gravity & set JumpVariable to 0
That way you simulate a bounce and you are able to define how many times it will bounce and can even set random values for gravity each time your object jumps.