the blockchain explorer shows my balance a bit lower than my the balance in my wallet. the difference is either 400 or 600 FIM, depending on when i check. so the different looks like 2 or 3 POS awards.
should i be concerned about this?
Yes we noticed.
You should not worry, it's just the blockexplorer scraper scripts that have a small error somewhere in the transaction/balance calculations.
This is not related to the FIM blockchain in any way.
Your balance in the client is your correct balance. We'll be working on fixing the blockexplorer scripts today.