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While you might get a bit more credit in the Royal Orchid program for that flight then you would in UA the value is quite limited unless you plan on crediting a lot more flights to TG as you'd not be earning enough for an award, effectively orphaning the miles.

My recommendation is to open a CO OnePass account and link it to your MileagePlus account. Then credit the flight to your OnePass account. While the award miles credit the same between OP and MP the EQMs are higher on OP so you'll be a bit closer to elite status and you'll get credit for those flights in your lifetime status counter as well.

To compare earning rates across a few of the *A programs (TG isn't included, yet) check out http://www.wandr.me/Tools/Frequent_F...g_Options.aspx.