How is the time reduction of Puggle calculated?

There seems to be 4 factors: The number of peggles hit, the bubbles value, something from the knowledge and the multiplier.

So how do these 4 factors combine to get the final percentage?

The end of the question is mostly what would be the best thing to aim for for a maximum reduction?

From a bit of testing while waiting for an item to be delivered, I have found out that it works as follows:

Every peg you get is added to the total value of the bubbles you popped. As such, the highest possible score would be to hit all the pegs - which have four rows of four, and five of only three, giving 31 pegs in total - and to pop all nine bubbles: three +1, three +2 and three +3, giving a total of 18 bonus from the bubbles. The total is then multiplied by .15% to give a base boost percentage, with a potential max of 7.35%

You then get the bonus from the Lucky Knowledge, which is +2% per level as of writing of this answer. This acts as a multiplier to the base boost percentage, with a maximum of 10 levels, or +20% bonus - making the potential max 8.82%

Finally, the dog bowl bonus (if any) is applied, which can be x2, x3 or extra Bux. This leads to a final potential max for a perfect game 26.46% - that's over a quarter of the time gone in one game!

It may have changed since the original response, but now it adds your peggle and bubble score together and multiplies by 2 or 3 if you landed in a multiplier bowl. The resulting score is multiplied by .15 to give you the PERCENTAGE of the original (not current) delivery time that gets taken off. As for the knowledge icon, it doesn't change based on how many brains you have, from what I've seen. My guess would be that it's related to the reduced delivery time perk in the knowledge tree. So, if you unlocked the first level, +5%, it would probably change to x1.05, and multiply your total score by that as well.

looks like it adds the number of Peggles hit and bubbles value then adds 2 to make the amount of seconds. Then is multiplies by whatever multiplier you got.

Peggles hit + Total value of bubbles + 2

So if you hit 13 peggles, and the your total value of bubbles was 10 and your multiplier was 3, you would get 75 seconds or 1 minute and 15 seconds off your delivery time.

So you would try to get as much as both as you can. But you will probably want more bubbles because they give you more than 1 'point'.

Hope this helped.