Not only what I mentioned in msg #17 but also the amounts of the N-P-K in the fertilizer mix that are water soluble and non-soluble. There could be two packages with one showing a higher number for the P however each of them is within a small percentage of the same water soluble amount.Both are 'bloom' type fertilizers, why is the Phosphorus element contained in both higher than that of their potassium counterpart? If I didn't know any better, just looking at the NPK ratios of both bloom fertilizers I'd reckon P was more important in bloom.
They both will eventually supply the full amount as listed except the water insoluble P will take longer to be available, sometimes a year or more.
Now if that is not enough to get you to go back and look at the list of ingredients once again here is something else that I have found myself thinking about when looking a the list of ingredients and that is "What else is listed after the 3 macro nutrients?".
Example is a fertilizer mix might not have the macro number(s) I am looking for but the package also supplies some Calcium-Magnesium. Is the trade off worth it? The P or K amount might be a bit lower but I am going to use it once a week anyway so is getting the Cal-Mag at the same time easier than mixing up a separate batch?