Final rinse products for colour emulsions contain more than just the surfactants found in black and white products like Kodak Photo-flo.
The colour final rinse products also contain bactericides, which are not required for black and white films, due to the anti-bacterial qualities of the silver in black and white negatives.
Most likely the colour final rinse products also contain other chemical elements that help preserve colour dyes.
Those extra components react chemically with the developed films in ways that both exhaust the chemical capacity of the final rinse, and produce byproducts that might impede function if allowed to build up.
So, if you are developing in a commercial environment that has a high throughput of film, to get efficient use from your final rinse you need to replenish the final rinse in an amount that both removes sufficient byproduct and adds sufficient extra chemical capacity for each film developed.
Fuji recommends a replenishment rate of 55ml for each 120 roll. So you take out 55ml of used, diluted to working strength final rinse and add 55ml of fresh, diluted to working strength final rinse replenisher to the batch.
Practically speaking that probably means separating a larger than 55ml portion of the solution from the rest, adding 55ml of replenishment, and then pouring as much of the separated portion back as is necessary to top off the tank.