Difference colons vs. commas in functions

Hi everybody and thank you for all the good tips,

I used to work a lot with trimmean and when I want add more cells from different locations I use ":"

I realized yesterday that

=AVERAGE($B$105:$B$146:$B$148:$B$181:$B$183:$B$217:$B$219:$B$291:$B$293:$B$304:$B$306:$B$346:$B$348:$B$388:$B$390:$B$392:$B$394:$B$448:$B$450:$B$475)
gives me 10.926

=AVERAGE($B$105:$B$146,$B$148:$B$181,$B$183:$B$217,$B$219:$B$291,$B$293:$B$304,$B$306:$B$346,$B$348:$B$388,$B$390:$B$392,$B$394:$B$448,$B$450:$B$475)
gives me 5.975
'Exactly the same array of cells but in one I use ":" to separate my cells and in the other one I use ",".

Why these two formulas do not give me the same result? if they are different, how can I use a formula like trimmean, which allow two entries only (separated by a comma), and still be able to select many cells from different locations?

Thank you for your help,

Julien