Changepackage addon

[SK Zai]

Hi, 

Subsequent to having invested a ton of energy attempting to investigate module logs, I can summarize my examination like this about Configurable Package Addon : 

You purchase a "Custom" cPanel (bundle named "Custom" in cP) trough WHMCS - > you got a cPanel account with Hosting Package named "Custom" 

You purchase a predefined cPanel (bundle named "Plan AAA" in cP) trough WHMCS - > you got a cPanel account with Hosting Package named "Plan AAA" 

Case 1: You update "Plan AAA" to "Custom" through WHMCS and you got a cPanel account with Hosting Package named "Plan AAA" (cPanel API use modifyacct/edit quota) 

Case 2: You update "Plan AAA" to "Plan BBB" through WHMCS and you got a cPanel account with Hosting Package named "Plan BBB" (cPanel API use change package) 

Do you know whether there is an approach to utilize {changepackage+modifyacct+editquota} for Case 2? Is it might be a bug? 

Many thanks to you for your assistance.