I received 4 $25 Type B Travel Vouchers (all in the same booklet) due to an involuntary re-seating problem on an international flight. 2 quick questions:

1) When the vouchers were issued, I noted to the service director at the gate that the GA that caused my problem had promised me a $100 voucher - he indicated that the 4 could be used together (even though they clearly state non-combinable) and that she was trying to do me favor with improved flexibility - is this true?

2) Can I used these on a ticket to which I also apply an e-cert (customer service)? In this case, I'd like to purchase say a $400 ticket, use a $200 e-cert and then use the $100 in vouchers to pay off a portion of the remaining $200 - is this possible?