Well, as stated above by another poster, there is a potential for suppression at higher doses. There's a conversion to 4-hydroxytestosterone which makes some hold the view that formastane products shouldn't be used in PCT. Though, IIRC, the conversion is minimal (I could be mistaken, if so, someone let me know).
I know from 4 squirts, I dry out and notice strength gains. Any more than 4 squirts and I noticed cramping (even with ample water) and achy joints (which impacted my lifts negatively). I think if someone was running a compound that increased estrogen levels, more than 4 squirts may be reasonable. Otherwise, I don't see the need to go above 4 squirts personally (Perhaps if you weighed more than me, there's a case).