OR given the fact that the show was originally planned on having a 1 and a half year run and syndication on TV (lasting only 80 episodes), they tried to be as close as the games as they could and they never expected that all their game adapting (as in direct adaptation of the numerical levels and the games only having 151 pokemon at the time, leading to them to saying there were 150 known Pokemon and "many more to discover" in the anime) would cause continuity errors in the future (since they weren't expecting the anime to become so popular and them continuing the series over episode 80).