How many twinkles will you get?

Haagen Dazs has a new 'Be Our Star' programme. Part of the details as follows:

"現凡惠顧於Haagen Dazs專門店, 可獲得相當每次惠顧總額的twinkles積分*, 如閣下現為Haagen Dazs貴賓卡會員, 出示貴賓卡更可獲取雙倍惠顧總額的twinkles積分. ...

*所獲得的twinkles積分以最接近及較高之$25倍數為準."

So here comes the questions:
1. If you are NOT a VIP and spend
a. $28
b. $74
c. $102
@ HD, how many twinkles will you get?

2. If you ARE a VIP and spend
a. $28
b. $74
c. $102
@ HD, how many twinkles will you get?

3. What kind of consumer behaviour will you think this star programme will encourage, assuming the consumers want to join the programme?