Just because I remember breaking my leg doesn't mean my leg is still broken.
That's what I'm trying to say. There's the physical planet and the mental planet.
The Mental planet remembers everything, the physical planet is affected by time travel etc. This may explain why even so, the "planet" has a grudge on the humans, even though it saved it.
But if there is only one aspect of the planet, and because we know that it is transdimensional, then it wouldn't it only show that it did lose energy if it passes time or whatever.
Though, it simply depends on what Lavos theory you believe. If you believe that he's always in the planet till 1999AD, then the planet is weak and would not have enough energy or shouldn't have that much to pull Dinopolis in. If Lavos dies forever, hence no 1999AD scenario ever again, then it explains why the planet "has a grudge" and actually remembers the whole situation.