What is the difference between IPA and Ethanol in terms of solubility?
[...] ethanol could be used in a solvent extraction of two solids, but it also says that isopropyl alcohol could also be used, but must be used in higher concentrations. Why? [...]


They hopefully didn't write about the "concentration of isopropanol" but mentioned that a larger amount of the solvent has to be used.

It is not uncommon that organic compounds with polar substituents are less soluble in higher alkanols.

Vanillin is a typical example, the solubilities are in the range of 4.15 mol/L in methanol, 2.5 mol/L in ethanol and 1.8 mol/L in 1-propanol. (Data are taken from a freely accessible collection of experiments performed by students: OpenNotebook Science Challenge). I couldn't find any data for 2-propanol. 


  So would this suggest that if one were to use IPA as a solvent, one could use the same amount of IPA as they would Acetone?


No, not really. A ketone and a secondary alkanol, although looking similar on first sight, may have behave completely different as solvents. Polystyrene (foam), as an example is pretty much insoluble in isopropanol but highly soluble in acetone!