United miles do not post accurately
 

Just an observation/warning - United miles in premium classes do not post accurately on the A3 account. It happened to me before and than I just thought it was a fluke but now when it happen consistently is probably not.

Examples:
DCA - ORD
Miles according to United: 612
Miles according to WebFlyer: 610
Miles posting to A3 for travel in Y class (1.5 multiplier): 891 (= 594)

ORD - IAH
Miles according to United: 925
Miles according to WebFlyer: 926
Miles posting to A3 for travel in Y class (1.5 multiplier): 1400 (= 933)
Miles posting to A3 for travel in Y class on CO (no multiplier): 925

So sometimes it works for you, sometimes it works against you. The only problem it is not predictable.

This is no such thing as 'accurately'. All programs have there own mileage charts, there is no 'standard' distance.

See above for ORD-IAH which should be the same distance no matter if the flight is on CO or UA. While no class bonus distance post correctly, with the class bonus the distance is not the same.

Of course each program has its own chart but even if we assume that A3 had its own chart to, for example ORD-IAH, than it should be consistent no matter which airline you fly on.

If you assume it comes out of United, than it does not fit to United own mileage chart.

At this juncture, to all Star Alliance members, CO and UA are still pretty much entirely different airlines, definitely as far as other FFP programs are concerned.

There are other examples which show the continued differences. For Domestic F seats on UA metal other Star Alliance carriers book a seat in 'O' and you therefore pay the First Class price. For CO it's 'I' and you pay Business Class price. So UA/CO haven't even sorted that out yet. They remain separate entities as far as awards are concerned.

As I said above, until UA and CO are one airline in all areas, and inform their Star Alliance partners that they are one airline, with one set of rules, these differences will exist.

I've had YVR HKG credited as different amounts before when flying AC vs CX.
Both were in 100% fare classes. (CX L, AC S).

There is nothing unusual about the variations. It's only 'un-reliable' in so far as you cannot be certain of the precise base mileage in advance - but the variations are minuscule.

My UA miles posted perfectly, as expected in the middle of the Athens business day today, Wednesday, for a domestic UA flight Sunday night. I was credited with the expected 1500 minimum miles for FC A class. Note that I was careful to associate only my A3 FF number with the reservation, never entering either a UA or CO FF number.

My UA OLCI boarding pass also said Star Silver as expected for the flight.

However the nice dragon in the UA lounge at ORD asked me what airline A3 was as she had never seen the code and thought it was Asiana.