Why make custom Accessibility Service if default TalkBack is there?

[t2mkn]

I have developed an App which is mostly like a Tool but has lots of Settings which is custom designed. I though to implement custom descriptions for Accessibility users. Did that, but at some point the TalkBack is not doing the right way. For example if there is a Seek control with content description it reads like "40% 1000 milliseconds Seek control" when selected. And at runtime when the control is adjusted the content description is updated accordingly, and then it speak like "59% 1476 milliseconds 59% Seek control". This is not acceptable I guess, it should seek like "1476 milliseconds" only not with the percentage. And if percentage is spoken it should speak once not at beginning and end.

If I implement a custom Accessibility service and if that is turned on, the speech can be customised. But will it be a good ideal to implement accessibility service just to adjust the speech for 5 6 custom controls?

So I want to discuss or find what other reasons are there for which I should implement Accessibility service?