This sounds like the guy who asked if he needs to mix the chemicals with water to spray the parking lot someone asked him to spray.
All liquid fertilizers will have a density figure on the label or MSDS. Sometimes it will be called "specific gravity," sometimes it will be called "weight per gallon." On the Ferromec 15-0-0 label, it says the product weighs 11 lbs per gallon.
So, that means that each gallon has 1.65# N in it. If you're spraying at 10 fl oz/M (M is the Roman numeral for 1000 and is used to represent 1000 sg ft; K is the chemical symbol for potassium), you are applying 0.128# N/M (1.65# N per gallon /128 fl oz per gallon * 10 fl oz/M application rate).
Isn't this stuff on the certified applicator's exam?