[JXLS2] jx:if(condition="..")? Excel Comment Markup Questions

[zitot-hawaii-edu]

I am working with jxls2, creating excel template and putting the jx:area and jx:each code inside an excel comment as getting started guide showed.

I wanted to make a sum row that only shows once the current row name is not equal to the previous row name. The documentation strongly supports that jx:if exists for this purpose. I maanged to do that.

I wanted to total some column for a dynamic range inside a column, display that in a cell, and thought of using a for loops from jxls, but could not figure out how to do it, or even if it is supported at all within the limitation of excel comment markup. Can someone confirm or deny this? A simple example would be great.
note: I know that jx:each is some kind of a forEach loop, but i wanted to nest them and save values and such.
Though it's better to offload that to Excel where possible, which is what I'm working on now. Well, if the Excel method doesn't work, it's nice to fallback on jxls.

By the way, the strict inequality comparison causes an error and I don't really understand why. I managed to use loose inequality operator instead to get the desired effect since that didn't work.
The report could not be executed: An error occurred when evaluating expression data[foo2].NAME !== data[foo2].NAME

I'm using Report Server (an open source product) which is using JSLX2 for the report engine, except that jx:grid is currently disabled as of most recent update due to a regression within report server itself I believe
Sorry if this is a trivial or unsupported question. I hope JXLS3 comes soon to us.