Likewise, the desktop script uses the ping interval to calculate hours, iirc, but you only get to set one value and then live with it forever.
In general: don't mess with the polling interval. Remember that it's stochastic. Even at 45 minutes you'll get pings that feel ridiculously close together, and pings that feel obscenely far apart.
Setting a 10 minute ping would kill me.
A longer interval is probably more defensible, when combined with a simple tagsonomy (sic) that anticipates and accommodates low variety.
For me, TagTime tells me how I'm actually spending my life, not my time.
When I want to track granular time-spent on something, I use a timer.
Automatic, manual, doesn't much matter. It's the difference between measuring the input and the outcome. One of the outcomes of TagTime goals is that you're relying on the co-incidence of the ping and the doing. I find that randomness stressful on emergency days.
As has been said, pings are sacrosanct or the whole thing is worthless.