That is great that you can grow Cymbidium. I have not seen your Cymbidium sinense, so I cannot judge the condition of the plants. What I hear from other Asian Cymbidiums when they grow in bark, there is very little new growths.
Also, when it is grown in the traditional Japanese Cymbidium pumice mix, you do not need to repot every year. Asian Cymbidiums don't like to be repotted every year. With this mix, you only need to repot 3 years or so.