Data knowing he gets emotions eventually (from Picard's stories) could have him delay the installation longer than he originally intended.
Worf and Troi quickly call off their relationship after finding out what happened in AGT. In the AGT future, Worf and Troi's relationship continues unhindered. Data then could have installed his chip right then and there to better observe relationships with his own emotional reaction or something (Data actually wants to feel happy for them or something), and he could have controlled his emotions by the time Soran came along, meaning the Ent-D is never destroyed. There are still quite a few months between AGT and Generations.
Certainly long enough for the Enterprise to spend a considerable amount of time in refit to get the new bridge stations, new Stellar Cartography and the hallway that bisects Engineering