ELC was founded in 2014 and you have actually used their transformer for 3 years now, it means that you actually bought a product with little or no proven track record of the product at the time of your purchase.
https://sg.linkedin.com/company/elcelectronicsco.ltd
Based on what I have read in various forums, recommendation on the size of the transformer needed is 2X the rated watts of the equipment that you want to connect to and majority of the users in those forums gave bad reviews on China made transformers.
For the transformer that I am using, it is not required to have a 2X the rated watts of the equipment that I am using and I feel safer with a thermal fuse.