sampling rate not respect with 9401

Hello,

I have an cDAQ 9178 with the 9401 on slot 2 and 9205 on slot 6.

I want to acquire the counter CTR1 synchronized with the AI clock of the 9205. To do that I use the DAQmx Timing and the DAQmx Read.

But, if I set 1000 S/s and 40S, I don't receive the Samples and the number of available samples increase until I received an error.

If I set 1000S/s and 2x40S=80S it works properly.

Why?