Dear Penthode, thanks for your reply.
But years ago, I was thinking the same way and found out Iam wrong.
The Sony KV-1300- 1310E and their UK versions were using the tint control just to avoid the PAL Telefunken license fees by modifiying the PAL decoding circuit. At least, they also using Delay Lines as of "real" PAL devices.
See circuit extract and photo of the device in the 1310E with Tint control.