IFElse Statements and Calculation within

Hi All

Trying to do a calculation within an ELSE IF Statement but not having any luck, can anyone advise on the syntax below?

Dropdown: Adjustment Type, Option Values (Plus, Minus)
Scheduler Rate: Currency = 650
Adjustment Rate: Currency = 300

If Adjustment Type DD = Plus Then (overallschedulerate = Scheduler Rate + Adjustment Rate = 950)
Else Adjustment Type DD = Minus Then (overallschedulerate = Scheduler Rate - Adjustment Rate = 350)

FORMULA BUILDER CODE

ifElse(add(equal($eadjustmenttype_c),"Plus"),$totaladjustmentrate_c,$totalschedulerrate_c)),
ifElse(subtract(equal($adjustmenttype_c),"Minus"),$totaladjustmentrate_c,$totalschedulerrate_c)))

Thanks a mil

Sean