Is that an official answer from support, or something you've seen with changing your own account?
The one reason I could see there being a catch would be that all plans increase by different amounts, so you could rack it up faster with L4, then downgrade & transfer it to L1.
Then again, they all increase so much/fast anyway, it probably doesn't matter.
I guess it would be less confusing if they worded it in a way where the increases apply to the customer, rather than the plan, like "You get an extra X GB of this and X GB of that per week, as long as you're hosted here, regardless of which plan you choose."
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