Aker, thank you for idea about manifest-files, but that didn't help me.
Compared 4338823 with 4345459 - seems that 4345459 has something new regarding 4338823, and later I thought that 4345459 can be installed without 4338823.
But then I made investigation on virtual machine (win7 x86) with all recent updates installed manually and with help of MS Baseline Security Analyzer (using wsusscn2.cab from 10.07.2018).
MBSA now always recommends 890830 (malicios soft removal) and 4130978 (time zone changes) - I ignore them in next story:
1. Uninstalled 4345459, 4338823, 4088878, 4099950, 4073578, 4056897 and rebooted. Those updates disappeared from system's installed updates list.
2. Run MBSA but it didn't recommend anything.
3. Removed 4338818, rebooted.
4. Run MBSA, it found missing: 4049068, 3004361, 3076895, 4054521, 3101722, 4338818, 4048960, 4338823, 4339093, 4038779, 4041678, 2509553, 4054518.
5. Reinstalled 4338818, rebooted.
6. Run MBSA - no missing updates, no recommendations again; only 4338818 appeared in system's installed updates list, 12 others - not.
7. Manually installed 4345459, just for test - it appeared in system's installed updates list, but 4338823 did not (as we remember, 4345459 is a fix for 4338823).
8. Run MBSA again - it does not recommend anything.
4338818 is cumulative (huge in MBs), released July 05.
After installing of it, MBSA does not recommend 4338823 (for example). But it's not clear - does it install it "insisibly" to user, or it makes "shut up" for MBSA not to display it.
I mean - can't say if 4338823 is really installed (released also July 05), 4345459 is released July 13, but WSUSSCN2.CAB is older and it don't "know" about that fix-update.
So I should conclude now saying that without manual checking with resources like:
https://support.microsoft.com/en-us/help/4088878/windows-7-update-kb4088878and
http://www.catalog.update.microsoft.com/Search.aspx?q=4088878end-user will not know actual situation, MBSA is unable to help.
Thank you for participation in discussion.
I guess, topic should be closed now and
no modifications should be made to WSUSoffline - I worry that this could make a lot of problems.