I have just gotten an IAE engine mod for MD88 turning it into an MD90. I’ve made changes to it’s performance to match the more powerful V2500 engines. I then decided to make an airframe for it on simbrief based on the MD88 since MD90 profile isn’t the best and doesn’t have performance calculator. What I unfortunately discovered is changing the ICAO code to MD90 in the airframe prevents me from using the perfromance calculator. Wouldn’t it be better for base type to be used to determine whether that is available?