I am finding the same issue with some exchanges as other members reported before me.

In this example I checked rates on OrangeFren and Swapuz exchange gave me the best rates,
but when I was redirected to Swapuz website I found different rates, and I refreshed page several times to confirm.






It's interesting that sometimes I am getting better rates than it was reported on OrangeFren wesbite.
For example this happened with Hellex exchange, I selected swap from BTC to XMR.




So maybe there is some issue with OrangeFren, not with exchanges trying to trick anyone.