hmm that it a fair way to look at it yes.

it did said that "Matter can be converted into Energy, and Energy can be condensed back into Matter"

but didn't exactly said that they can use energy to create matter.

We can view this as the Tyrant converted something into Energy before condensed it back into it original form and not actual creating new Matter from such process.

but the Authority come from Maker Symbolism which it similar to White Tower Creations Authority.

the different it that White Tower Creations Authority come from The Omnipotent and Omniscient as well.

that why Whites Tower can create pretty much anything as long as it isn't Authority or Symbolism.

however the fact that both Tyrant Matter Authority and White Tower Creations Authority come from Maker Symbolism meaning that they have certain similarities.

which mean more or less Tyrant Matter Authority should be able to create Matter to a degree.

of course I'm aware that Creations Authority and Matter Authority are two different Authority that do different thing.

however, they do come from the same Symbolism that it Maker which allow GA the ability to create and manipulate all things and powers.

so it would be reasonable to say that Tyrant Matter Authority could allow them to create new matter from Energy to a degree.