looking at the table 8, Balanced Saturation of K, Mg, & Ca on page 47 of the Midwest Labs Agronomy Handbook.

At first look I was thinking you have almost beach sand at 3.9 pH. not a fairly high 22.5 CEC.

Potassium between 224 ppm & 300 ppm K

Magnesium at 275 ppm Mg

Calcium at 3,000

Using the another system at 3,150 to 3,600 ppm Ca.

The rule of thumb allows 10 lbs/A N for each unit of CEC Say up to 200 to 240 lbs/A Nitrogen.

We have a major HERE & THERE thing going I know I can apply 1,200 lbs N to my 50 CEC soil and have the N persist for 7 years. That is maybe 24 lbs N/ unit of CEC.
In some of the East Texas sands they need to apply fertilizer every 21 days for grazing dairies. Regardless of the amount applied it will all be gone in maybe 6 weeks, THERE.

Now I hope you take up tissue analysis. In it you will find that phosphate is very touchy on the amount of P in the plant. .
Mg is a little less touchy.
K is very forgiving on percentage of K.
Ca does have it's limits on both the high end and the low end, but I will never see them in this soil with my crops.
Young Billy Albrecht was infatuated with the Magic Cation Balances. From my perspective the Cation Balance percentages are interesting but do not apply with a soil that is 95% Ca. That only leaves the remaining cations trying to fit in the last 5%.
Here the calcium levels are what they are and will not change in many lifetimes. Now with the Computed CEC just by dumping additional K, Mg, & Na on your soil the COMPUTED CEC will increase. A Computed CEC is an apparent figure not a measured value. For a Computed CEC Midwest will charge you $40 a sample.
A Computed CEC is K + Mg+ Ca + Na+ a consideration for pH.

For this season 200 lbs of potash fertilizer will probably work. Then us you tissue analysis to make adjustments. If you think you NEED a lot of K then apply it all in the fall. If you think you need a dab of K anytime will due. If you are hurting for K side dress several times during the season.

This is the opinion of a semi ignorant Texas Hay Farmer.
Note I have never seen 180 bu of corn, not in this county.

Have a Grand and Glorious Season.