Timothy usually loathed spending a massive amount of system points, or mana points come to think of it, but in this particular situation that they were in, the prior was justified. A purer mana quality on its own wasn't enough to survive the squabbles of The Old Sea, not with the team's current levels that is, so he had to rely on the grand modifications that the system offered in order to survive. With enough upgrades, even his level six mana could look and act gigantic!
The purchase that the system recommended the most, was the amplification of the Dual Casting trick that he used so often! Dual Casting wasn't a power or an ability per se, it was just a thing that came naturally while a mage progressed, and in this case, the system could alter it so Dual Casting would cost less mana points to initiate!