Hmm... I don't agree with your method of stress testing your game, but that's another matter.
For comparison these are the last few entries of my MemoryBlocksLog in a typical game I have, which is a full STEP installation plus one or two additions.
195 108 196 108 218 108 218 109 218 110 218 111
This is with my skse.INI settings as this:
[Memory] DefaultHeapInitialAllocMB=768 ScrapHeapSizeMB=256
This means I could quite easily lower that to 512 and still see no issue. Which brings us back to a matter raised earlier: lower your initial figure and retry.
Are you absolutely sure that log is updating and it isn't a leftover from a previous install? Do you have your MemoryBlockLog.ini setup like this:
Any other setting and your logs may not be created or they may be residing in another location to that you expect.
Lastly if your game can safely run, modded or not, with normal playing then this utility is not needed, all it does is log how memory is used, not improve its use.