I am using 1.17 firmware, but the 109 still seems to have issues with 16x media.
I have 16x Verbatim (-R and +R) and 16x BeAll -R discs.
BeAll is restricted to 12x burning with a QS of 92 and a burn time of 7.22 mins.
Verbatim -R burns at 16x in 6.55 mins, which nearer 12x performance, but with a QS of 96.
Verbatim +R burns at 16x in 6.38 mins with a QS of 50. However, if burned at 12x, it is faster at 6.04 mins! QS improves to 90. Both suffer from a large spike ~ 2.3Gb.
Taiyo Yuden and Maxell overspeed to 12x with good quality.