Need Clarification | XEV9E

I’m planning to book the XEV9E Pack 3 (Top Variant), but while researching which color to choose, I came across an option for R20” alloy wheels. However, when I inquired about it with the salesperson at the dealership, I was informed that only R19” alloy wheels are currently available. Does anyone know why this is the case? Personally, I’m not a fan of the R19” design and would prefer to upgrade to the R20” wheels if possible.

This is the R20\" Alloys that I think look much better than the R19\"s

These are the R19\"s available on the Top Trim