I reread this thread as I was confused about a couple of things that were stated.
At the beginning of this post your stated you just bought 10 bags of fert from a "new" supplier...then in another thread you state that your customers could tell a big difference from you "new product" vs. using the Lesco fert.
If you are going into a lawn with a 10% Fe product (which you only used 10 bags) then of course they are going to tell a big difference. But you will not ever use this product every time!
Again you need to compare apples to apples when comparing product performance and price!