It really depends upon the mission at hand as that will drive equipment needs and can for the most part predict time on target. The force protection assets that have been assigned to the task may also play a part with regards to equipment and ammunition carried by each individual.
Depending on what Unit you are with may dictate personal equipment and load out. I see a lot of people running with about 4 mags, three on the man and one on the gun for in and out jobs. I personally believe that each mag should be contained within its own pouch, that way you won't have to worry about a partial stacked with a full mag in the same pouch. That being said, a partial should always go in behind the furthest full mag when double stacked so all full mags are at the front and you should work from furthest to closest.
During break contacts, partial or empty mags will go to the same location, dump pouch or down the shirt for patrol operations and like you had mentioned, re-set when the patrol is firm and secure.
For CQB and prosecuting a single target, there would be very few occasions that team members would expend front line ammo during the assault phase. To that end, partials can be placed back into the vest pouches during the re-org phase and prior to a back clearance. However, if there is a period of consolidation during the fight through, it would behove individuals to conduct a tactical reload when they have the opportunity. For example, when conducting CBRNE operations there should be frequent periods of consolidation to ensure there are no tears or holes in suites or hoses. This is typically done using buddy checks, perfect time for tactical reloads if you have partial mags.
If the there are multiple targets in a complex of buildings then urban warfare SOP's may be applied and personnel may be required to carry more ammunition and more equipment i.e., ladders, explosives, more frags, double front line ammo etc. During these types of operations where fighting may surge then slow, allows time for squared away personnel or 2IC's to ensure that ammo is managed and topped up. Placing partials inside of dump pouches is not wrong by any means and I too place empties in cargo pockets.
At the end of the day, no one is really going to tell you that you're wrong if you getting the job done right! Having the dump pouch on the front provides the team member with flexibility and a quick and easy way of placing a partial mag in under stress and recovering mags without having to be at full ROM of joints just to get to them.
Our Dump pouch has the ability to roll up and out of the way when not needed, it also has a velcro closer at the top together with a draw cord and barrel lock. It can fit store chemlights with elastic sewn in and can hold about 5-7 mags. It's made from 500 denier nylon and is available in several colors.
I hope that answers your question.