Christmas Question (spoilers)

So, Mushroom goes into the future to Christmas - four months after his time - and his future self is standing there with the future sci-fi club and he hands himself a remote as though he's expected to arrive. I guess a simple explanation would be that he just planned to make sure he would be there on that day with the remote 4 months after his return trip - like Bill and Ted's Excellent Adventure. The problem I have with that is that everyone in this film is kinda stupid and this action would be the single most intelligent thing anyone does in the film. Also - nobody seems to question it. It seems that Mushroom is a bit of a moron too, so expecting him to remember to be there on that day is a bit of a stretch for me. Maybe they explain it better in Japanese, but the subtitles are incomplete... I have the Region 2 DVD and the subs don't seem that bad. The only thing that really felt incomplete about the timeline was this issue... it's the only thing that relied on an unknown - the future... everything else that happens (including Mushroom's real time) is present time. Plus, he knew they were going to be getting a new AC unit later. I don't know. I'd like to hear some ideas...