Hi tetroid, welcome to CDFreaks!
The RITEKF1 discs are in fact 16x rated discs, but the firmware in your LG drive doesn't recognize this media code, and that's why it only lets you select a default 4x burning speed.
There might be support for RITEKF1 in a newer firmware for your LG GSA-22L, but I'm not that familiar with your drive so I can't say for sure.
If you have another 16x DVD burner, it's possible that your media is supported at up to 16x in that drive. Although 16x may not give you the best burns.