Is it common to have an indent and/or flatness under breasts after a breast lift with implants?

It can happen depending on how tight the closure was along the vertical incision line.  Usually the implant will stretch this out and give it a normal contour but it may take a few months.  If ok with your surgeon you can massage this area to see if it improves faster.  

No posted before & after photos... So can only recommend you return to see your chosen operative surgeon, Dr Krau to discuss. Or seek paid in person second opinions from boarded PSs. 

That is an excellent question! It certainly can happen with this procedure, especially if the closure was a little tight.  It often will resolve with time as the implants drop into place and the skin stretches out--that can take months to occur, sometimes 3-4.  Speak with your surgeon to see if implant massage will help (if you aren't already being instructed to do so).  If it doesn't resolve on its on, several months down the road you may be a candidate for fat grafting to that indented area on the breast. In this procedure, fat is removed from one area (such as the abdomen or flanks) and reinjected into the breast to correct asymmetry and/or add volume.  Hope this helps.  Good luck!