Trying to maximize mileage combining a business trip:

Required:
1- Trip to Sao Pablo and Buenos Aires in consecutive weeks.
2- Stop over in US (Newark) prior and after the trip
3- Trip to start in London (although I am based close to EWR)


Tentative RTW ticket:

LHR-xAMS-DTW through KLM/NW// (First Stopover, independent side trip to Newark and return within 7 days)

DTW-xEWR-GRU through NW/CO (Stopover in Sao Pablo: 4 days )

GRU-xIAH-EZE-xIAH-EWR through CO (Stopover in Buenos Aires: 5 days, and later stay in Newark for few weeks)

EWR-xNRT-xAMS-LHR through CO/KLM (End of trip -> return to EWR with a prior open ticket I already have)


At first look seems to respect all rules and get just short of 39,000 miles, but would like to know if I have overlook something.

Basically:

Seems that I don't transfer more than twice in same city:
- Transfer twice in AMS
- 1 Transfer and 1 Stopover in EWR
- Transfer twice in IAH

4 Stopovers: DTW; GRU; EZE; EWR

More than 10 days

Area 2 -> Area 1 -> Area 3 -> return to Area 2

By NW agent it seems that there is no problem to backtrack North-South within same "Area", therefore, US-S.America-US-S.America-US seems to be allowed while don't transfer more than twice in the same city. Is this correct?


Appreciate your feedback and welcome your suggestions. Thank you!