LMSC it never earns any interest; it’s a free run for these super rich companies in the name of building up for winter
If you want to bother to change DD payments twice a year or even more often, there is nothing to stop you doing it - or at least, I can change my DD whenever I want. When I was with PurePlanet (until it went belly up), they automatically set the payments to be 25% lower than average during the 6 “summer months”, and 25% higher during winter - this meant I was closer to zero net balance through the year.
However, considering the best savings account are around 4% AER (but overdrafts are usually >35% APR), running an average credit of say £500 (+1000 in summer, 0 in winter) doesn’t lose me much in terms of interest, and it may just save me some overdraft charges (all I’d need is 11 days of overdraft on my monthly £500 energy bill, and I’m ‘net zero’ against the lost interest).
As usual in these things, YMMV…