Should we calculate tipset state every time?

[Noc0r]

I'm implement a new feature, based on lotus realization. It makes a message, which contain a new type of actor: this actor is responsible for init/retrieve storage operations. But the problem is of multiple execution for tipset: every time, when it computes a tipset state, also executes all messages in this tipset. My actor init a new deal a lot of times instead of once. Can someone explain, why we can't keep it in ipfs with tipset info? Also i have a question about role of cron actor. Unfortunately, i didn't understand this moment :^(
Thank you!