Does higher RWIN increase packet loss ?

The TCP Window does not create packet loss.

By definition, if there is packet loss on your line, the higher the throughput, the more packets you are going to lose, however this is offset by the higher amount of data being transfered.

A higher buffer (TCP Window) causes more data to be present in the line between you and the server. It allows for higher throughput. In the presense of congestion and packet loss, more data in the line means more data has the chance of being lost. However, the percentage of lost data is not affected by a larger TCP Window value.