Rotating the dish (ie. modifying the skew angle) changes the position of the 82 LNB while maintaining position for BEV 91.
Given that the BEV91 feed is central, rotating the dish (modifying the skew angle), will not affect the pointing of the BEV91 beam but it will affect the polarisation(skew) angle of the BEV91 feed.
The position and polarisation of the 82 LNB beam will change as the dish is rotated. The position of the beam will vary up and down. Note that when the polarisation angle is approx correct the feed will also be in approx the right position.
With two feeds the line between the feeds is the polarisation angle or slope of the curved line of the orbit. As Greg says you might have the two feeds both set slightly off centre and aim the dish midway between the two satellites. This makes sense if the signals from each satellite are similar level. If one satellite has weak signals it would be better to to use the central feed for that satellite since outer feeds generally give lower performance; this is the case where extra feeds have been added to dishes designed for just one feed.
These figures may help:
Satellites due south of you have polarisations which are about nominal. Satellites to the south east have polarisations which are tilted anticlockwise, facing the satellite. The figure shows the possibilities of 5 feeds or 3 feeds on the dish. The pattern of the feeds is a mirror image of the sky, so in the case of the three feeds, the central feed will be lower down and the two outer ones slightly higher. The polarisation angle is approximately level. For perfection, it is possible to adjust the polarisations of each feed individually and also the spacing to suit the orbit positions.
Best regards, Eric.