Actually I mean a longer you let your position opens, a more interest you will have to pay for an exchange and therefore even if your position is at profit when you close it, you will have less profit at the end.
It is now clear that funding rate could be $0, positive (which would be added to your trading fund), or negative (which would be deducted from your trading fund. Funding rate can not be used to determine that the longer the trade, the higher the money a trader would pay. Which payment re you talking about?