The combo pack doesn't include a full pound of each:
Fertilizer Combo Pack $14. Shipping is $5.10. Cash based payment price. $20 shipped for Credit/Debit based payment.
1 lb KNO3
1 lb K2SO4
½ lb Plantex CSM+B
It's more balanced (proportion-wise) to what you should be dosing. The individual ferts should run out at similar times.