When I got my used Sonata a little more than a year ago, it had been on a steady diet of dealer conventional 5w20. The change in the sump when I bought it was about 5 months old but had only about 400 miles on it. I ran it out to 3200 miles and did an UOA, it seemed fine. It was posted here. It was down to the bottom mark on the dipstick when I changed it though.
Since then I've only run 5w/10w30. The engine seems slightly quieter with it. However, it's still down to the fill mark by 3500 miles or so. I just shrug it off and top off.
The 4 fills since the dealer fill were:
M1 5w30 5200mi - sampled, but not sent in.
Havoline ProDS 10w30 7800mi with 1 qt top off ProDS 5w20 - no sample
Havoline ProDS 5w30 8100mi with 1 qt top off ProDS 5w20 - no sample
Havoline ProDS 10w30 current fill, about 500 miles.
The reason I topped off with 5w20 was that I have a single jug for top off for both cars, which previously was a Dart for my wife, now the Outlander which is still on factory fill, hopefully won't need top-off.
I'm going to back off on the OCI for the ProDS - I saw a UOA for this where the TBN retention wasn't the best. I will sample this fill and see how it is, and at that time send in the M1 sample too.