I have a trip to Lembeh Straits in September and October 2014 and just got a message from Silk Air that they have dropped the number of days that they are flying from Singapore to Manado and back. I happened to be flying back to Singapore on one of the days they dropped so had to make changes to all of my flights. Based on what I found out they are now only flying there on Monday, Wednesday, Friday and Saturday. Some of the people in my party had booked through Singapore Air or with a travel agent and they or the agent did not even know there had been changes to the reservations.
If you are headed that way you might want to check with both Silk and Singapore to make sure your flights have not been changed.