[pferreira]

Originally Posted by CyberCubed

The opening changed in mid-Season 4, so you can pinpoint the time the show was renewed.

Hopefully this helps: "The fourth season of Teenage Mutant Ninja Turtles is split into two sub-sections that aired concurrently: thirteen episodes which aired daily in syndication, and twenty-six episodes that premiered in hour-long double-bills on Saturday Mornings on CBS, which would serve as its home for the remainder of the whole series. A brief "Turtle Tips" segment aired between the two episodes which served as a PSA about the environment or other issues. There were a total of 20 "Turtle Tips" segments produced and aired. The syndication episodes featured the original title sequence, while the CBS episodes debuted a new title sequence, and also did away with the show's title cards.

During this season, the Technodrome is back in Dimension X, having been launched from Earth through a portal at the conclusion of season 3 .[1] The season premiere, "Plan 6 from Outer Space", aired in syndication, and detailed how the villains' battle fortress crash-landed on an asteroid; in the later episode, "The Dimension X Story" a volcano on the asteroid erupted, immobilizing the Technodrome by surrounding it with molten lava.[2] "The Dimension X Story" was evidently intended to be the first episode of the CBS run, as many other episodes which aired before it from both the syndication and CBS episodes refer to the Technodrome being trapped in lava, but wound up airing very late in the season."


http://en.wikipedia.org/wiki/Teenage...es)_(season_4)

To answer your question it is possible CBS made the deal but didn't have time to finalise it before new episodes were to be aired so the syndicated episodes were made first before the deal was set in stone. Notice also the CBS episodes have a slightly bigger budget for animation.