If the score skips from 49 to 51, this will not work.
Instead I'd go for something like:
- add to score: f.param(0)
- add to scorespawner: f.param(0)
- call function "scorespawn"
while scorespawner >= 50:
- create object
- substract from scorespawner: 50
All actions that add score would then use the addscore function instead of simply adding x to score.