In the majority of merger announcements the multi-tier bit is usually ignored. That is the first problem and gets the affiliates irate from day one. The multi-tier is just as important to some webmasters as the players. That said, the gambling industry isn’t the only one to ignore it. Just ask the Rapid Satellite affiliates who were kicked out of the program after they decided to terminate all overseas affiliates.
For those programs that are merged into one that doesn’t support multi-tier then some form of compensation is due. Easiest way is to perhaps look at average earnings of a period of time, eg 6 months, and make a lump sum payment. Not ideal for everyone but something is better than nothing.
For those that already support a multi-tier, I fail to understand what is so difficult. If you can map players then you should be able to map sub-affiliates. Once again I think technology difficulties is being blamed when it shouldn’t. Somewhere in the old system the sub-affiliate is linked to the affiliate so what is so hard about querying the database to get this information and then updating the new one?