Calculating DAX memory sizes

Hi,

I'm trying to learn & understand DAX memory usage, as I'm getting the "... exceeded the available resources..." message in both Excel and PBI Desktop. I've read other posts and Chris Webb's blogs on the subject. I'm now using DAX Studio to analise the query, but am having trouble seeing how it is exceeded the memory. We're using Premium Capacity (P1) which has a 6GB query limit.

Here is a screen shot of the DAX Studio Server Timings, highlighting the most intensive step and estimations:

This step appears to only use 368,277 KBs or 368 MBs. Totalling up all of the others memory costs comes in at under 0.5 GBs, which is well under the 6GB query limit on the Premium Capacity.

What am I missing?

Thanks

Scott