This was fixed couple months ago, iirc. At first the game only checked for the videoclip, but now it checks for "poolparty" variable that is set to false at the start of v0.18 and only set to true if Ash answers "That's awesome!" to Tyrone's invite.
If you're having issues with it probably you're playing a corrupt savegame. Try using the console to set to false "poolparty" just before going there or better yet start v0.18 from the beginning, it's almost the same time as the invitation takes place very early in 0.18 (v0.17 ends with the camgirl session or at home after college if not camgirling).
TLDR: Yes, Tyrone's pool party is avoidable even if Ash did the videoclip.