Upon closer examination of what you are doing, if you will notice your picture shows ST1 ($On) as the input to the CTREGRD. This will not work. CTREGRD's input leg is edge-triggered as denoted by the little triangle. When I experimented with this my raw count was stored in .iReg2 and the scaled RPM value was in .fReg1 because I chose floating-point in the scaling. If, however, I chose the scaling to be integer, then the raw count was still showing up in .iReg2, but the scaled RPM value was not in .iReg1 instead of .fReg1.
However, each execution of the CTREGRD instruction would read the raw counts value in .iReg2 each time. But this is not a continuous read. As franji1 pointed out, there is no need to do a CTREGRD instruction unless you are trying to remember a count on a power-up or something. But that's another story.