Small scientific outposts aren't going to be able to contribute much to major civilization 'big science' efforts. Much of their time will be spent solving local problems, and doing basic local science. It will take a while to document the planet, and develop the local expertise to handle 'Big Science' projects. So established colonies will be more efective at research than new colonies.
The best way to model this is by giving every planet a 'science cost,' based on the number of people and buildings and planet class. The price should go down with time, to reflect familiarity with the planet, but it will always be there as local resources are applied to solving new planetary management problems. So a planet can initially cost more science than it produces, eventually it will break even, then grow, but it will always be paying some research as maintenance.
This could be a way of fighting "Tech Snowballing," and possibly aid vertical strategies, by slowing the rate at which new colonies produce meaningful increases in research.