UOB PRVI - 10X the rewards - Is it real?

Dear friends,

My UOB credit card statements for the respective months are as follow:-

• May 2010 - I have spent $3,237.27. I "earned" 1,082 UNI$ and was credited with 3,426 UNI$. 
• June 2010 - I have spent $1,550.12. I "earned" 504 UNI$ and was credited with 3,824 UNI$ and deducted 2,344 UNI$.
• July 2010 - I have spent $1,550.12. I "earned" 777 UNI$ and was credited with 2,313 UNI$.

When I saw the deduction in June's statement, I immediately called for a written and detailed explanation for the deduction. About two weeks after my call, a general letter to all affected cardmembers to apologise for the deduction was received. [Can a bank deduct someone's account before informing the account holder first?]

As that was not the letter I had been waiting for, I called its call centre again. On 16 July 2010, I finally received the letter with detailed computation of UNI$ transaction by transaction.

Here are my confusions:-
a) What is the formula to compute the UNI$ I earned against the amount spent? Based on the letter dated 16 July, it is very apparent that my various transactions earned different UNI$. Example - $930 expenditure earned 372 UNI$ whereas a $174 expenditure earned 68 UNI$.
b) Why the number of UNI$ credited is about 3 times the UNI$ you said I earned based on the 3 statements above? Why is the amount earned and amount credited be different?
c) UOB said (in small print) in its promotional material that only FIRST 5 transactions totalling $1,250 would earned 10X rewards of 2,500 UNI$. So if my first 5 transactions is less than $1,250, then what do I earn?

UNI$ or loyalty points are treated like liabilities and governed by respective Financial Reporting Standards. As a cardmember here, I am having trouble understanding UOB Credit Card's UNI$ rewards system. I wonder whether its auditors and Monetary Authority of Singapore are able to make sense out of all these.

The above is presented as factually as possible for the respective authorities to review and also for fellow credit cardmembers to be more vigilant and aware of issues I am facing.