Not directly applicable but perhaps related data point:

I stop spending on my reserve card when I hit $60k + buffer. On occasion there has been an inevitable refund which results in a statement credit balance. In those instances a negative skymiles entry posts to my account when the statement closes. This is generally in the area of a hundred dollars or less. If the overall spend for the year drops below the $60k I spend a bit more -- I have never tempted them to claw back a large bonus or MQMs, so I do not have a directly applicable data point.