Currently, if I add several segments (without breakdown), Total will be a sum of all the numbers which is not useful for me because of segment overlap.

I would have expected 117k instead of 199k. If the Segments Total was empty, then the percentages below could use the above line as a base. Currently, the percentages on the bottom right always show (in sum) 100% or 0% when there is no data...
Your suggestion ("Show Value As - % of column total") is good, however parent total, % of the above would also be sufficient, i.e. further breakdowns' % can refer to the above only, instead of Grand Total, and have a value/sum of up to 100%...