I can't vouch for the 1771 platform as I've only used these modules on the 1734 Point I/O platform. But on that platform, the VHSC is basically the same as the IJ/IK but with configurable high speed outputs on it as well.
So, if you were using the 1734 platform and looking only to measure, I'd be pointing you at the IJ/IK (difference between IJ and IK is the voltage) since you have no need for outputs.
Perhaps check to see if the same holds true for the 1771 platform?