Thank you so much for your help! I've just found out that there is Tiger BKK-CRK $90 on 30.01 21.20 which may actually be even cheaper than ZED BKK-HKG-MNL and doesn't require travelling MNL-CRK. I'm just a little bit afraid of a possible flight cancellation since I've heard that it happens quite often to low-cost airlines in Philippines...