Yeah.. hard to say... I thought that I have no time to check without error reporting... but now that I borrowed that time, I just realize that I have to to do it again with a modified update pack... Problem is: rvkroots.exe is 8,0,2195,0 at least since 20150313 (and AFAIK that was the Version some times before also).... rootsupd.exe Version within "5er_UpdatePack_XPx64SP2_2015-07_1" is 41,0,2195,0 which is the latest number "5er_NT5.2_EoS_Delta_Addon_2015-12_1" within the rootsupd.inf opened within the rootsupd.exe within 5eraphs installer matches (though the *.exe(s) itself will show just 5eraphs Version of 1511 and/or 1512 (*1) to nlite and be therefore always under 38.0.xxx.xx or whatsoever...) and just the .sst files (within rvkroots/rootsupd.exe) have a different SHA* checksum number over all those installers available (and 5eraphs one mathcing the latest .ssts from www.download.windowsupdate.com/msdownload/update/v3/static/trustedr/en/**.sst) - so I am not sure how to verify what is actually installed.
I don't consider it a valid test... but I now have changed the version number within the .inf for the rootsupd and rkvroots included in the delta addon with 2198 instead of 2195 (default) and shall see what happens.... (as said, I don't see it as a valid test, as I changed within 7zip entries for files within the addons)...
*1: [Correcting myself: for rootsupd.exe its Version: 6.0.6000.16386 vs. 1.5.0.2712 and for rvkroots 6.0.6000.16386 vs... the same as before... so it is not the version number from within the inf nlite verifies, but the one from the self-extracting cabinet files .exe (IExpress vs. 7zip)]
... but still.. stay tuned for the results: And Void/NUL/NIL/etc.
the modified pack with a source: WMP11+KBs slipstreamed, just 5eraph Update Pack, IE8 Pak+Delta AddOn (Modified), be it with Error Reporting or not... leave no traces within: HKL\Software\Microsoft\Active_Setup\Installed_Components... Grmpf...