Real rate of lindex sell fee?

Having noticed a difference between estimated profit and real profit i started investgating and found out that according to the difference between the gross and net profit values (which should have at least adveraged to 3.5%) came out to be an adverage of 3.525% with a high of 3.5405666%.

It states on the fees page that "Sellers of Linden Dollars pay a fee of 3.5% per transaction."
not 3.54%.

Anyone else noticeing this?
Is this normal?

You didn't specify whether you did a limit sell or a market sell. When you do a limit sell, it will most likely be filled by a handful of market buy orders and the rounding starts compounding since the seller's fee is calculated per buy order, not per sell order. The more buy orders it takes to fill your sell, the more the percentage deviates from the 3.5%.

If you use search, you'll find this has come up a number of times before. /139/65/150882/1.html has a post from Lawrence Linden.