Latency tune CASA C100g

Hi all,

is there any way to tune latency for customers connected to casa c100g cmts via docsis 3?
There is around 20ms latency what is quite a lot (someone say that is normal) but i want to know if there isnt any way to tune the latency to reach 4-5ms stable?

Sometime i can see pings around 4-7 ms but most pings are in 15ms - 22ms range.
Thankx a lot

Here is a confiig of my upstream interface:
spectrum-rule 1
frequency 53800000
channel-width 6400000
power-adjustment continue 6
map-advance dynamic 400
no rate-limit
ingress-cancellation 100
pre-equalization extended-taps
logical-channel 0 profile 3 secondary-profile 102,101
logical-channel 0 minislot 2
logical-channel 0 pre-equalization auto-reset
no logical-channel 0 shutdown
logical-channel 1 channel-width 800000
logical-channel 1 profile 101
logical-channel 1 minislot 8
no logical-channel 1 shutdown
no shutdown

spectrum rule 1
cm-hop
channel-width 6400000 800000
action modulation channel-width
back-hop-limit 3 2
correctable-fec threshold 15
uncorrectable-fec threshold 2
profile 3 snr-threshold 330
profile 101 snr-threshold 260

modulation-profile 101
request atdma qpsk off 64 0 16 338 0 16 fixed on 1 1536 qpsk0
initial atdma qpsk off 640 5 34 338 0 48 fixed on 1 1536 qpsk0
station atdma qpsk off 384 5 34 338 0 48 fixed on 1 1536 qpsk0
a-short atdma qpsk off 84 6 75 338 13 16 shortened on 1 1536 qpsk0
a-long atdma qpsk off 96 8 220 338 0 16 shortened on 1 1536 qpsk0

modulation-profile 102
request atdma qpsk off 64 0 16 338 0 16 fixed on 1 1536 qpsk0
initial atdma qpsk off 640 5 34 338 0 48 fixed on 1 1536 qpsk0
station atdma qpsk off 384 5 34 338 0 48 fixed on 1 1536 qpsk0
a-short atdma 16qam off 104 12 75 338 6 16 shortened on 1 1536 qpsk1
a-long atdma 16qam off 104 16 220 338 0 16 shortened on 1 1536 qpsk1

changing map-advance dynamic 400 to 200 or to stacit havent changed anything on latancy.