The count of each possible multiplier depends on whether four or five Bonus Spots were hit, as shown in the table below.
The return is shown in the table below for any number of picks and catches.
As you can see, the base game return for all number of picks, except three, ranges from 37.0% to 37.2%. I want to highlight that this is based on the paytable, which is likely the most generous available. Most casino slot managers will go for the more conservative option.
At least four Bonus Spots have a 0.012737 chance of being caught. 94.9% of the incentives will be awarded for catching four Bonus Spots, while 5.1% will be awarded for capturing all five. At least four Bonus Spots have a 1.27% chance of appearing.
For catching four Bonus Spots, the average multiplier is 387.5%. The score for catching five is 784.21%. 407.58% is the weighted average.
2101.26% is the weighted average of the number of spins per bonus. The final average number of last spins per bonus when considering infinite possible bonus retriggers is 2869.18%.
Overall, the bonus feature is worth 2869.18% x 784.21%= 11694.41% times as much as the main paytable. We get a bonus value of 1.27% x 11694.41% = 148.95% times the value of the base paytable when we multiply that by the bonus likelihood.
The total return to the player from both the base table and the extra feature is shown in the table below.