We have the following settings:
"Crafting rate bonus mulitplier (apply oxide perms for additional mulitpliers": {
"vip1": 25.0,
"vip2": 50.0

When I give VIP the permission to "vip1" the craft speed is 25% of the normal time (TC will take 7 secs)
When I give VIP the permission to "vip2" the craft speed is ALSO 25% of the normal time (TC will take 7 secs)

If our settings is the following (we switch the rate from vip1 to vip2):
"Crafting rate bonus mulitplier (apply oxide perms for additional mulitpliers": {
"vip1": 50.0,
"vip2": 25.0

Both give 50% 😅

So it seem it only takes what vip1 are set to, and ignore speed on vip2

Also, when "Simple Mode (disables: instant bulk craft, skin options and full inventory checks for better performance)" is set to true, the crafting speed multiplyer does not work at all.