Originally Posted by WineCountryUA

The $900 is a guaranteed upgrade and for SFO-AMS, very unlikely to get much lower -- not usual to see >$1,000
20K miles + $550 is the standard miles+copay offer for your fare class, it will not go lower. Note if this is waitlisted, you will have uncertainty if it will clear and without status, that is even greater uncertainty. If you value miles at $.015 per mile, this means it is equivalent to $850
If you want the upgrade, I would take the $900 --- it is guaranteed and similar in cost.

Note SFO-AMS is a new flight and early on may be weak on demand, hence the lower offer
AMS-SFO inaugural flight on 31 Mar