Much too complicated for my lazy brain to critique. But the proof in the pudding is tongue weight shown by a tongue weight scale. Does the tongue weight scale confirm the accuracy of your spreadsheet results?
If you don't have a tongue weight scale, you can get wet and loaded tongue weight with two passes over the CAT scale. The first pass with the trailer tied on, but without the spring bars. The second pass without the trailer. Add the front and rear axle weights, and the difference with and without the trailer is tongue weight.
You also need the CAT scale report in the middle of a towing trip after you fill up the SUV with fuel and after all passengers return from the loo. The CAT scale report will give you front, rear and trailer axle weights, as well as gross weight of the rig. (Not tongue weight or trailer GVW).
You need two trips across the CAT scale to determine the percentages of tongue weight that is distributed to the three different axles - one with the spring bars not attached, and the other with the spring bars tightened to where you think they are properly adjusted.
My wet and loaded tongue weight was 570 pounds per my tongue weight scale.
Without the spring bars:
Steer axle =3040
drive axle = 3880
trailer axles = 3480
gross = 10,400
With spring bars tightened:
steer axle = 3280 = 240 pounds increase = 42% of tongue weight
drive axle = 3520 = 360 pounds decrease = 210 pounds remaining on the rear axle = 27% of tongue weight
trailer axles = 3620 = 140 pounds increase = 25% of tongue weight
gross = 10420 (20# scale error)
Conclusion: Hitch needs more adjustment to distribute less weight to the front axle and leave it on the rear axle. Goal is 25/50/25% and we now have 42/27/25. So try reducing the tightness of the spring bars by one length, then change the angle of the ball mount to the shank by a few degrees. Then weigh the rig again with the spring bars tightened, and check weight distribution again .
Grumpy ole man with over 50 years towing experience. Now my heaviest trailer is a 7,000-pound enclosed cargo trailer, RV is a 5,600 pound Skyline Nomad Joey 196S, and my tow vehicle is a 2012 F-150 EcoBoost SuperCrew.