No - in DC where the OP is located 99 is the highest, then 101 and then 103. If he were on the west coast, 99 would be the lowest, then 101 and the highest would be 103.
My high school geometry tells me that the tilt setting is setting the dish so the plane of the LNBs is parallel to a line drawn between the three satellite locations. In simplistic terms, that would mean that if the 101 signals are great but 99 and 103 are not, there's a tilt problem. If 99 is good, 101 is so-so and 103 is poor (or the other way around) it's mainly an elevation issue. If all of them are poor, it's probably an azimuth issue, although a big error in elevatiion can have the same effect..
Hi Texas brit.
What you call tilt I call twist or skew. Tilt for me is elevation.
I will remember about the height in the sky of the sats depending on where you live. Thanks