That means for example someone holds 1000 PMC and the TX fee for any transacation will be calculated on this amount? Well when this someone makes a lot of small transaction he pays a lot of fees, when he makes a single big transaction the fees are much less of course. Fees should be only calculated on the amount which is transferred with a min. and max. tx fee.
No, he doesn't. He pays exactly the same.
Example;
Tx Fee @ 0.1% per 1 PMC (rate is based per 1 PMC for ease of understanding)
Person A:
Moves 10 PMC 10x times.
0.1% fee = 0.1 PMC Tx fee x 10
RESULT: 1 PMC
Person B:
Moves 100 PMC 1x time.
0.1% fee = 1 PMC Tx fee.
RESULT: 1 PMC
It does not matter if you move 1 PMC or 1000 PMC, the amount of tx you pay is exactly the same. It's just relative to how many PMC you send, as the TX fee is charged per 1 PMC. 0.1% is just an example. 0.01% would be perfectly fine.
You can't cheat it, and you can't be punished by it. The more you move, the more you pay. The less you move, the less you pay, But most importantly, everyone pays the same.
It's simple and it works. Easy to understand, potentially easy to implement, and easy to work out what it will cost you to send your PMC. It needs to be simple, but relative.