Bonus is collected ONLY from the Spin saucers when the spin lands in Bonus, Double Bonus or Triple Bonus.

Here's the scoop on Fan-tas-tic from my Classics Guide:

Fan-Tas-Tic [EM – Williams, 1972]

Quickie version: UTAD.

Go-to flipper: Mild bias Right.

Another UTAD game, but I’ll cover the basics. The primary feature is the under-playfield wheel, which scores the value the ball lands in when you shoot into any of the three “spin” saucers, one at the very top, the others on the mid-lower sides. The wheel values are 3000 (2 of these), bonus (2), double bonus, triple bonus, advance bonus to top (10K), open gate (ball return in right outlane), Light A&B lanes (for 3000 per shot) and three “stars” which award an extra ball when you get all three (should be off in competition).

There’s a “ball return lane” (kickback) in the left outlane that’s activated by hitting the center stand-up target.

Bonus is earned with the two small rollover disks near the top and the two side-of-center stand-up targets. Maximum base bonus is 10K. Bonus, both single, double and triple, is scored by the wheel. Bonus is not collected at the end of the ball, only from the wheel via saucer shots. Bonus resets each ball.
The game has one of those nasty center-drain bumper layouts that can eat balls often unless the bumper is very active. If the bumper is weak, try to keep the ball away from it. If the bumper is strong, try to encourage it to pop the ball back up where you can flip it away.

You can cradle balls on the flippers and should do so when possible. You can also lose the ball under the flippers if you miss-time a flip when the ball is near the bottom bumper.

Optimal strategy is just flip the ball up top all day via the A and B lanes and hope to collect bonus advances, wheel spins and the various awards therefrom, i.e. bonus collections and lighting the A and B lanes. Don’t bother shooting at the three center stand-ups, nor the two side spin saucers. All of those are too risky. I list the flippers as mild bias Right because shots up the left “A” side go up to the top saucer area, while shots up the right “B” side are fed into the top bumpers directly.

BTW, D&D Pinball was a great arcade in downtown Tucson that was a victim of the pandemic. They used to have the state championship there.

Just get the ball on the 'Bonus', 'double bonus', etc hole on the wheel

You shoot the pinball into one of the "spin" saucers. The large multi-holed roulette-like under-the-playfield saucer then spins; where the small ball in that saucer lands determines your reward. Note you do not control where the roulette ball lands; it's like a regular roulette ball.

I regret selling mine it was one of my favorite EM games to play.