Or simpler based on LittleStain answer :
This is a question of comparison sign.
As long as the object is less (and ONLY less) than the desired size, you make it bigger.
Once it is bigger (and ONLY bigger) than the desired size, you set it at the desired size.
Without the "or equal" in your comparison, you're making sure the logic works as intended.
You are also making sure that as long as the size is less than the desired size, the object will get bigger. The moment the size is reached, it won't grow anymore.
And you are also making sure that it will be bigger than the desired size only once, since the moment it happens, you set it to the desired size which no event/condition actually acts on anymore.
Replace 80 with any value, and it will work, as long as it is consistent in both events.