I don't believe this is tariff abuse, but thought I best check before I book...

I want to spend 2 weekends in Berlin shortly, however CE is very expensive and redemption availability is patchy, so the plan is...

Fly LHR-HAM-LHR on an Amex 2-4-1 in Club, 4 weeks apart (Friday - Sunday), and fly TXL-LHR-TXL in between (Sunday - Friday) on a paid non-flexible CE ticket. I'll get from HAM to Berlin and back on the train (I have a Bahn Card 25, so it's discounted anyway), but I may also squeeze in another BA flight in between the two Germany legs (either LGW-AMS-LGW, LGW-GLA-LGW or LHR-DUS-LHR, all Fri-Sun returns).

Am I likely to get pulled up for this?