if whatever it is you have to do is worth more than than 300$ I would do it.

To give a comparison India had some air space restrictions this week which meant my MH flight from SIN via KUL to BOM was delayed to arriving to 0200 in the morning on Tuesday. As I had a busy day on Tuesday including an internal flight I last minute booked another J flight on SQ obviously at a seriously higher price. I cancelled my MH flight and will eventually get a refund minus SGD 75. However I got over 100K in new business and I'm fairly sure being "with it" rather than totally knackered on Tuesday as a result of rebooking was a great help in securing the business. who knows...but a small price to pay for a better night sleep for whatever you have to do the next day.