It is never a good idea to mix your moisturizer and sunscreen together. The ingredients that make a sunscreen work have to be in a set combination. Throwing your moisturizer ingredients into the equation will totally reduce the effectiveness of the sunscreen.
It is like mixing chamomile tea with beer, or mixing 2 food recipes and get a sloppy/messy tasteless result. So NO Mixing… Use moisturizer where your need it, and sunscreen everywhere.
However if you have 2 mineral sunscreens of at least 10% Zinc + Titanium, and 1 is very white and ghostly, then mixing it with the TiZO SPF 40 will give you a lighter tint without reducing the effectiveness too much. Do not try this with non 10% mineral sunscreens.
More sunscreen info at SkinCareTV channel on YouTube.