Why do some designs have fixed sizing options?

Certain plate design and format variations have limitations on size adjustments. For instance, if you choose a Richmond Tigers plate with a 3-letter and 3-number combination [6-Characters], you can only purchase this design in a regular size; the slimline option is not available due to the position of the Richmond Tigers logo on a slimline plate size. Similarly, if you opt for a Motorcycle plate, there is only one size option to choose from, and alternative designs are not available in this case. Certain 7-character plate combinations may only allow for slimline plates to be selected due to certain character sizing.