I totally get where youre coming from, I outsourced before I got my mill, and youre right that time is money.. Im a one man lab, and a busy month for me is around 100+ units.. I could take on more work if I didnt mill and sinter them, but it would almost be a wash. This is more math than I care to do this early, but whether you outsource 120 units, or I mill 100 units, the profit could be the same depending on what youre charging. I wasnt trying to convince you either way, especially if you dont have the room, becuase it does take a lot of space and power to mill and sinter in a small lab.
For me, Im a control freak, I dont want someone else coloring my zirconia, I would say that is the hardest part of the process to get perfect, but if what argen sends works for you, then dont mess with success. For reference, the total time it takes for me to take a designed crown, nest, mill, desprue, color, is less than 3 minutes per crown.. however if you do that 120x, thats 6 hours/month. Ive always found it takes longer to fill out a rx form again for every case and upload. When you add in the shipping cost, to me, it just doesnt make sense. I paid my first mill off in a year, used it for several years, then sold an asset to purchase another. Ive since purchased 4 other used mills that work better than the fancy new one I bought..