On the angle master, are the numbers on the second line DPS?
The second line is only used when working with the MB-100.
https://www.tormek.com/usa/en/accessories/other-accessories/mb-100-multi-base/
I should have said the bottom line. If I set it at 15 degrees it should be a total of 30 degrees. When I do this it seems like I am doing a lot of of reprofiling. Y hen the sharpened bevel it wider than when I started.
The second line is for the angle between the flat part of the AngleMaster black piece and the wheel at the point of contact of said piece. This works well for chisels, it works for knives as the TOTAL angle if you can actually rest the anglemaster on your top edge and not the flat of the blade. So you have to have a really wide bevel for this to work.
If you rest it against the flat of the blade, then you measure the angle between the edge and the flat of the blade. So you actually measure dps+half of the blade spine angle (angle between the two flat sides). Back to your issue, if you set it at 15 degrees and your blade angle is 4 degrees, then you grind at 13°. The anglemaster is useless to SET a given angle precisely.
Yes, if you want to set a precise angle, you'd better use one of the calculators and measure the distance between the USB and the wheel.
For replicating an existing angle, the Sharpie method is more appropriate.
To answer your question, yes the bottom line is the one you use, and if you set it on the side of the blade, it's the degrees per side (dps).
There could be several reasons it's taking a lot to reprofile. (The obvious is the original angle is high, many higher than what they're advertised at). And if it's a thicker knife, or was originally sharpened at a higher angle than thought, the bevel can end up wider than expected.
As tgbto stated, if the knife has a taper from spine to edge, this will lower the sharpening angle, unless compensated for. I describe it more in this thread... What angle is this knife sharpened at? (https://forum.tormek.com/index.php?topic=3573.0)
Finally, as micha stated, consider using a calculator (https://connect.calcapp.net/?app=qq0pg0#/), although it doesn't just have to be if you want a "precise angle" (although it does that), but just a better way to set the angle on knives.
Thank You all so much for your comments. I understand much better now.