Let's say you got 239 hours last race, you get 241 hours this race, does that mean you only get 1 point from this race and no leftover hours?
Uh? I think you would get 2 points, and with zero hours left. Let's try with an example:
A. Always carry overRace 1: (0 from previous)
+ 239 hours --> no points, all 239 carried over
Race 2: 239
+ 400 = 639 --> 2 points, 159 carried over
Race 3: 159
+ 200 = 359 --> 1 point, 119 carried over
Race 4: 119
+ 50 = 169 --> 0 points, 169 carried over
B. Carry over unless you get pointsRace 1: (0 from previous)
+ 239 hours --> no points, all 239 carried over
Race 2: 239
+ 400 = 639 --> 2 points,
159 carried over reset!Race 3: 0
+ 200 = 200 --> 0 points, 200 carried over
Race 4: 200
+ 50 = 250 --> 1 point,
10 carried over reset!I think this would make things more difficult for those who stay in the lead for longer; in particular, it would decrease the incentive to keep the top position in the last third of the race, leading to more uncertain finales.
Might be completely wrong though

Carrying over, as you pointed out, means that LTB goes from being a "race score" to a "season score". We could just sum up all the leading hours and assign
floor(hours / 240) points at the end of the year. I don't know if I like that :\