Assuming a US gallon & quart, 5 (US) gallons would be 5 * 4/3 = 6 2/3, not 9. A 6-gallon US (5gal IMP) batch would be 6 * 4/3 = 8.
Also 4 * 22oz is 88oz, whereas 3 quarts is 96oz...
I'm not really confident either way on the spice issue, although it stands to reason that if the baseline calls for an amount a scaled up version would call for an equal scaling... the various ingredients in this aren't what comes to mind when I think of "spices". Although now I think about it, I'm not sure what else you'd call something like vanilla.