so if there isnt any specific diff between Withdraw, all people will chose lower one to To have money in their wallet, its safer than keep mined amount in the pool balance. am i right???
It's always safer to have the money under your control
if you can manage to keep your wallet and seed safe.
Your initial questions are rather unclear.
* Keep in mind that transaction fee may or may not be the same as the withdrawal fee from a service (usually the services charge a bit of extra, although this should not happen with mining pools).
* Keep in mind that one transaction with multiple inputs is still cheaper than multiple smaller transactions. Also if you have a big number of small inputs in your wallet it will be more expensive to spend them. On the other hand, if you don't trust (yet?) the service you're using, it's clearly advised to withdraw more often and maybe consolidate your funds.