Your male is not clearflight pied because clearflight only affects the lower wing and flight feathers, making them clear. I originally thought he could be a recessive pied, but on closer inspection, his cere is the mature blue colour and he has colour on his chest instead of his lower body. Male recessive pied budgies' ceres stay pinkish purple (the immature colour) their whole life.
To answer your question about combination pied, it's a mixture of the two main pied types: recessive and dominant pied. Recessive pied is recessive, which means that it needs two copies of the gene to be visual. However, when combined with one SF dominant pied gene, sometimes the genes mix a little bit, leaving a budgie which exhibits some characteristics of both dominant and recessive pied.
Double dominant pied budgies have two dominant pied genes. Because dominant pied is dominant gene, it only needs one copy to be visible, so when there are two copies of the gene present, it's like having double the "pied" markings, making the budgie very clear of markings.
Here's some pictures for comparison:
Double factor dominant pied budgie:
Single factor dominant pied budgie:
I hope that makes sense! I can't wait to see the pictures