Microsoft will have a Security Bulletin, in this example MS13-099
Once you open the bulletin you will see that there are (in this case, but not all) many affected products (OS and or applications) and many KB articles (2892074, 2892075, etc) that fall under the bulletin.
The way that LANDesk patch definitions are created, they have to break things down a bit and target the different OS's and applications differently. If you open MS13-099 in LANDesk you will see 5 different detection rules. In this case, the rules are for Server 2003 and XP systems and the actual patch files are .exe's
If you open MS13-099_MSU you will see even more rules and if you open some of these rules and look at the affected Platforms you will find that they are for Win 7, Win 8 and Server 2008 and newer. The actual patch files for these are .msu, which is what MS provides for these newer OS's in most cases.
The reason you are seeing more systems detecting the _msu patches are because you appear to have more Windows 7 or Server systems than Win XP, or you patched the XP systems already but not all the Win 7.
The INTL and ENU (and other languages) differ for various reasons.
The short answer is, LANDesk needs to break these down.
In the end, if you have systems detecting these security patches, be it _msu, _INTL or whatever, you will want to patch them after you have followed your internal QA and whatever approval process you have.
We patch all security related items.