Hi Ram,
I faced the same question that you faced, and I requested by an incident SAP for a resolution. They told me, that you have to set in SDA the base level of your AIO to 700, prior adding SAP_ABA 700 to the main package importing condition.
Doing that, I was able to import a PAT-file, that was build on 7.01, in a 7.40 system.
Regards, Stephan