I think it's pretty clear.
The part about combined spells seems to be the source of the confusion, but to me that only means that you can combine Time Spells that requieres Temporal Sympathy (most of the spell that can use it are essentially useless without it) with other spells. It's not supposed to expand what spells may use the attainment. For example, you could Rewrite History to give someone a skill dot in a skill he doesn't have, and then use a Perfecting Mind spell to augment it. You are not augmenting the skill in the past, but in the present. Rewrite History and Temporal Sympathy just gave you the one starting dot you needed to use your Perfecting spell since you cant cast a Patterning one.
unlike Sympathetic Range, Temporal Sympathy can only be used on Time spells that call for it and other spells Combined with them.