There are three main reasons why the maillepedia does not list this entry under the name "Full Wyrm".
The weave Full Wyrm was found to be Fire Wyrm with sequential reinforcement and dilation applied.
Dilation does not change the weave from being a sequential reinforcement of Fire Wyrm.
The sequential reinforcement can be applied to the other wyrm weaves which creates the need for there to be differentiation in the naming between which wyrm weave is being sequentially reinforced.
In the interest of clarity and consistency, I listed it under Fire Wyrm - Sequential. More information about sequential reinforcement as well as its application to the wyrms (and other weaves) can be found in the following article:
What's the Difference? The answer to the question of "What level of change to weave structure constitutes a new weave as opposed to a variant?" will vary depending on who you ask. However, it is indisputable that even minor changes in weave...