Comet Cast on Freeze Energy Cost

I understand CoF was nerfed in the last patch and energy generation was severly reduced.
But i find following values in the tooltips of Cast on Freeze very confusing:

The tooltip shows a maximum energy of 300 if i socket comet into cast on freeze. But the cast on freeze tooltip states it should have 10 energy cost per 0.1 cast time. Comet has a 1 second base cast time so shouldn't this mean 100 energy? Or if the total cast time in the tooltip of comet also gets considered for the calculation at maximum 200?
I just don't understand how the 300 energy cost gets calculated.

For example I tried to socket Frostbomb (0.5 sec casttime) and the max energy in CoF correctly shows a value of 50

The total cast time for comet is 2 seconds (one from the top + 1 to total from the description). But yes, it should be 200...I can't figure out how they came up with 300 either.

We at least need some clarification from GGG on this. The same happens with Lightning Conduit which is another "+1 second to total cast time" spell. Very unintuitive at best, bugged at worst.

Please GGG, let us know if this is intended behaviour, if it is, please explain here and provide in game tooltips.

Thank you.

Yup, i've noticed that also.
From what we can read it should be 100 Energy
I can understand that it goes to 200 but then it's computing from total cast time, not just base.
300 feels just wrong and unfair.

OK so, this is not a bug. If you hover over an underlined 'Energy' to get the tooltip it says that any modifiers to total cast time are doubled for the purposes of energy. This means, base cast time 1 second, +1 total cast time which is doubled for +2 giving 3s total cast time for the purposes of Energy.