Dear @lubos
why are Totals present in Inventory Quantity Summary?
Inventory Items should be grouped with Subtotals if the have the same Unit (and without Grandtotal) or there should not be any Total at all.
Take them away and await a rush of complaints 
But yes, they are meaningless by and large
What is the objection? It allows a user to know, “Last month, we sold 12,584 items, only 2 of which were returned.” Or you can quickly assess your inventory control protocols by comparing total write-offs to opening balances. Give me 30 more more seconds and I am sure I could think up 10 more applications.
The issue is that you are summing apples with oranges.
In our inventory, since we manage real estate investment funds, I have square meters of buildings, and percentage of participations in companies.
Summing 300.000 SQM of surfaces with 90 % of a participation in a company it doesn’t make sense at all.
It was just a suggestion for @lubos for a further implementation. You can have totals only for items with the same units, with the same custom fields, a flag to disable totals… there are many solutions.
However keep calm, I can alter the report in Excel by myself. I don’t want to steal 30 or more seconds of your precious time that you can spend to polemicize elsewhere in the forum.
I think you would admit that your use of inventory items to represent things like ownership percentages is fairly unusual. I applaud your creativity. Meanwhile, I have worked for companies where exactly the use cases I cited were common, although crude, measures of performance.
There have been many forum discussions over the years about totals. (In fact, there is another going on today.) My position is consistent, even if it is not obvious. Totals are good where there is useful information to be gathered and they do not confuse. They are questionable when there is no accounting or managerial utility.
Since the Inventory Quantity Summary does not mention units, I do not personally think totaling harms anything and has several convenient applications. I admit, those applications are not rigorous accounting, but neither is a report that does not mention units of measure in the first place. On the other hand, totaling quantities on a sales invoice can confuse shipping and customs personnel, so should probably be avoided.
It’s unusual but it is not creativity, it’s a law requirement as for Alternative Investment Fund Managers Directive 2011/61/EU and Italian implementation under the so called “TUF”, ie DL 24/2/1998, n. 58
I meant your creativity in implementing this in Manager.
I can onestly say that we can achieve with Manager, thanks to @lubos and a lot of our fantasy, what other Investment Managers using costly software don’t… by far.