once = one
time; on one
occasionYou can't use the other, but you can use the other time.
one time for X days and the other time for Y days =
once for X days and the other time for Y days.
You can use once ... once ... or once ... the other time. A similar choice is possible when a time is not involved. Either of these is possible.
There were two objects blocking the road. One was large, and one was small.
There were two objects blocking the road. One was large, and the other was small.
New2grammarOn second thought, why didn't you say "the other" in place of the second once?
Short answer: It's not as funny that way.
CJ