System Update Uninstaller question

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Ran Diskcleanup as administrator and it said I had around 400mb of system updates to uninstall, thinking back maybe it said service pack to uninstall? Anyway, I didn’t do the cleanup, but ran bleachbit and it said I had around 800mb of update uninstallers. I don’t understand the differences. Anyway I ran the Diskcleanup and did the 400mb of cleanup thinking that it would reduce the Bleachbit number by the 400mb. It didn’t, now Bleachbit says I have 661 MB of update uninstallers. Part is I think Bleachbit deletes Internet Explorer updates.
If I go to c:\windoes\softwaredistribution\download I show 631MB of data.
My question is does bleachbit update uninstaller delete data in c:\windoes\softwaredistribution\download?
If I do delete data in c:\windoes\softwaredistribution\download will my next Windows scan for update think I haven’t updated and download them all again? I was thinking if I wrote the scan for updating I would check release in program itself, but can see it would be quicker to check downloaded updated directory. But it would be even better to build table with nothing but update release K number and not actual data that came with the update. I don’t think they do that. Yes, I know they save the full updates so you can back them out, but there is a useful time limit on doing that.

BleachBit version: 
Your operating system: 
Windows 7