FYI, I'm at 37* 22" N which means that my ELEVATION should be @ 37* 22". Declination for my area "should" be 5.62* but if I put those two together I had problems with a "new to me" dish I setup recently! Lucky for me I already had a BUD setup in my yard that was working on both C and Ku so when I moved the second dish to my house from a neighbors 2 miles down the road and had problems, I just went to my other dish and copied the angles from that one to the "new to me" one I was having problems with.
Turns out that my old BUD was on 39* elevation and about 4.5* declination so I put those numbers in the "new to me" dish I got from down the road and things started looking better! Made one more declination adjustment and now I've got a bunch of sats that are showing me quality in the 75 to 95% range from 121 back to 72 degrees and I'll continue to add sats back to around 40*W within the next few days.
So I said all that to say this, those numbers you get off those websites are "starting points" only as manufacturing tolerances on these fabricated parts are probably out in left field somewhere and I wouldn't consider those as "absolute"!
Oh, and if there is a dish somewhere near you, you might want to go see if you can have the owner put that one on due south and take some angle measurements on it to give you a little help. For the look angle from the post I took a compass and shot an azimuth across the face of my already working BUD and transferred that to my "new to me" dish and it worked well enough to get me on my first satellite.
Just think of all this as if it was easy, then anyone could do it!