Array Formula vs vBa code - How To Modify My Messy Code To One Of Those

Hia all,

in the attached workbook, you can see (if you follow that mess of cell formulas) that I have been using a combination of COUNTIFS, SUMIFS, COUNTIF and SUM to arrive at the figures of 11 training sessions in which a total of 145 people attended. I noticed that this can take a varied amount of time - on my work machine (which is where I'll be using this workbook), it can take 10-15secs to recalculate for each new row that's added to the sheet "Attendances" - on my home supercomputer, it takes about 3-5 secs to recalculate - I can only imagine that this will get worse as the database grows?

So, what I'm wondering is this...

a. would a single array formula be able to accomplish the same outcome and if so, would someone be willing to show me how it should be written?
b. would vBa coding be able to do the same and again, would someone be willing to show me how?
c. which would be the faster of the two methods?

Ideally, given the wealth of knowledge I've seen here, an example of both, if possible, would be great - however, I'm not in a position to negotiate, lol, so I'll take whatever advice anyone can offer.

Cheers,

AJ