Why problem? It is simple mathematical task, not problem…
%ResultPrice% = 15 x OneYearLic + 20 x (9/12) x OneYearLic
And your license will be unified…
Otherwise contact other reseller or support…
to complement Pada with the translation of his answer
yes, the reseller can deliver a new license file which will have all the licenses in it that you purchased.
Just make sure you tell him to merge your licenses and that you want to use the file in ADNM.
if he cant help you then you can e-mail sales@avast.com to get it done for you
you need to mention your contractnumbers that are on both licenses and ask if they can merge it for use in ADNM