3 PWMS and RPM measurement with 9178 chassis and 9401 digital module

I want to have 3 PWM control channels and 1 RPM measurement channel using a 9401 module and the cDAQ-9178 chassis. I want to make sure I'll be able to utilize all 4 counters, as I think according to some reading that this may be a problem if I am using timed loops in my program. If this will indeed be a problem, is there any other hardware I can purchase or will I need to look into upgrading the chassis?

Thanks.