... You must've gotten the wrong file, then...
"mpas-fe.exe", whether 32 or 64-bit, is the standalone offline installer for updated anti-spyware (as) definitions; this file should only be used to manually update Windows Defender, Vista's native anti-spyware solution!
"mpam-fe.exe", whether 32 or 64-bit, is the standalone offline installer for updated anti-spyware (as) + anti-malware (am) definitions; this file should only be used to manually update MSE (NB that when MSE is first installed, WD is being de-activated, so as not to conflict with MSE, which is both an anti-spyware and anti-malware solution!)
You should probably only download from the (revamped) Microsoft Security Intelligence portal:
https://www.microsoft.com/en-us/wdsi/defenderupdates
Definitions for MSE there get updated 3-5 times during the course of 24h, but probably once a day is a sane frequency to manually update... You can read the Release Notes below:
https://www.microsoft.com/en-us/wdsi/definitions/antimalware-definition-release-notes
... for latest as well as the previous 19 releases...