Looking at your .C3P file the issue is clearly what I mentioned before.
When you're in the "all" mode, you are asking the creep object to regenerate the entire 1920,1080 area. Total pixels = 2,073,600.
When you're in the "area" mode, you are asking all creep instances to regenerate a 256x256 area around themselves. Total pixels = 65,536,000.
You can test this by changing both events to "pick random instance" you will notice no change in the "all" mode, as this is the same calculation, and the "area" mode will be significantly quicker (same as "all" mode), as it is only doing a single 256x256 regen.
If you change the "area" mode event to use a "for each creep" loop. You will get the same result as the original events in "area" mode.