Well, if your optic is Mil Dots...and you have MOA turrets, then your first mistake is choosing that combo. Now you have to know both units and how to convert them if you want to use your reticule for hold over.
Does yours have the "MilDotBar" system that has dots as well as thin lines between the dots?
If you don't know, you need to study your owners manual so you know how much over you're truly holding.
Most of what I'm about to say, will probably just confuse you, since your program, turrets and reticule are set to use different units of measurement, but...
If you made contact by dialing 23 MOA on your turret, and then held up one mil dot (or 3.438 MOA)...you most likely were making contact with around 26.5 MOA. This of course, depends where on the target you actually hit and if in fact you can place 3-4 more rounds into a group with a 1 MOA diameter at that range.
For argument sake...lets pretend you placed 5 rounds into a group that measured 8 inches(sub MOA)...and the center of that group was dead center.
Essentially, we could conclude that you would be truly "centered" which would put your hold for 906 at 26.5 MOA.
Using the atmospheric data you supplied...and the BC of .330, your velocity to be on target should be in the very close neighborhood of 3230fps.
This velocity spits out a solution of 26.5 MOA at your supplied atmospheric conditions and BC of .330.
The 23 MOA you dialed...plus the 1 MIL you held over (3.438 MOA) equals the roughly 26.5 MOA you actually need with that velocity.
To check...you should be able to back down to 5 MOA at 400 yds or 8 MOA at 500 yds and be right on target. Use a BIG target, shoot a 3-5 round group and go off the group center. Don't trust a single shot.
IF YOU ARE ON...then you know your velocity is truly at 3230.
IF YOU ARE NOT or you can't make hits at other ranges...then you need to run a scope tracking drill.
This video shows you how to do it. He uses 3 MOA adjustments...but I like to do 5 MOA adjustments.