Do ATB upgrades affect the overall charge time?

From some experimenting i did myself a atb bar with 3 slots takes about 4.3 ~ 4.4 seconds to charge. increasing the amount of gauges increased the times a little but not by a significant amount +- 0.2 seconds.

Here's a table of my findings

Atb slots | Recharge Time                    
----------------------------------------------
3         |   4.3 ~ 4.4 seconds
4         |   4.5 ~ 4.6 seconds
5         |   4.7 ~ 4.8 seconds
6         |   4.8 ~ 4.9 seconds

To answer your questions:

Yes upgrading the number of ATB slots does increase charge time. But at 6 charges you pretty much have an efficiency of around 180% compared to the charge speed at 3 slots

to confirm, here are my recharge averages:

ATB level | full recharge | recharge per bar

3 | 4.32 | 1.44

4 | 4.46 | 1.11

5 | 4.66 | 0.93

6 | 4.79 | 0.80