Nexos

You don't have to spend all of the mana on the same cost.

You can spend mana generated by the granted ability on any part of a cost that contains X generic mana . You're not limited to spending it only on the X generic mana part.

A "cost that contains X generic mana " may be a spell's total cost, an activated ability's cost, a cost to perform a special action, or a cost you're asked to pay as part of the resolution of a spell or ability (such as Condescend). A spell's total cost includes either its mana cost (printed in the upper right corner) or its alternative cost (such as flashback), as well as any additional costs (such as kicker). If it's something you can spend mana on, it's a cost. If that cost includes the X generic mana symbol in it, you can spend mana generated by the granted ability on that cost.