If it sounds OK, stick with it.

A possible (theoretical?) hiccup using the internal mixer might be caused by the fact that its a totally digital operation.

There may be combinations of mixer (and effect?) settings that could cause internal overload in the digital domain which sounds diabolical! This hasn't happened on my Y2K - but it has happened on my Yamaha YMF744 chipset PC soundcard!

Conversely, digital attenuation at some point in the chain results in a loss of signal resolution that cannot be recovered by later amplification.

These factors are one reason why "serious" digital sound systems are moving to 24 or 32 bit precision - more room to manoeuvre!