The 1602 requires 30% less current, it's noise spec is part of the LOL spec so it's not a weak link. It also shows better low frequency linearity and phase control than the 1612. Check the data sheets and look at the large signal step response graphs. They are different scale so not as obvious as it looks but the 1602 still looks better overall. iBasso may just prefer it for this particular purpose. Most of us know just enough to be dangerous.