I've never heard that about Clotho killing Typhon before... That is generally attributed to Zeus.
And in any case Typhon is not usually considered a Titan. Sure, he is a son of Gaia, but he was born after the Titanomachy. The Giants (Gigantes) are also sons of Gaia who warred against the Olympians after the Titanomachy, and they're not generally counted as Titans.
Of course the definition of "Titan" is kind of loose. Beyond the twelve original Titans the term is often applied to some of the next generation e.g. Helios (son of Hyperion) and Prometheus (son of Iapetus) but not to the Olympians of the same generation (e.g Zeus is son of Cronos and Rhea).