I moved to snap and found my latency time to previously connected servers had increased around 20ms.

So I ran a traceroute to citylink.co.nz (citylink) in Wellington, where my DSL modem is:

[Fred@fc9 ~]# traceroute citylink.co.nz
traceroute to citylink.co.nz (202.8.44.4), 30 hops max, 40 byte packets
 1  10.10.10.10 (10.10.10.10)  0.817 ms  1.762 ms  1.745 ms
 2  192.168.1.1 (192.168.1.1)  6.712 ms  6.700 ms  6.682 ms
 3  p202.124.98.202.snap.net.nz (202.124.98.202)  28.629 ms  31.606 ms  32.596 ms
 4  snap-chc-state2-rtr01.snap.net.nz (202.37.101.254)  33.546 ms  33.530 ms  33.509 ms
 5  snap-wlg-cbdpop-rtr01.snap.net.nz (202.124.98.195)  41.469 ms  41.462 ms  41.441 ms
 6  ponte.wix.net.nz (202.7.0.6)  42.393 ms  28.742 ms  32.753 ms
 7  rufer.citylink.co.nz (202.8.44.97)  34.687 ms  34.658 ms  34.643 ms
 8  zidane.citylink.co.nz (202.8.44.4)  37.575 ms  39.532 ms  40.499 ms
[Fred@fc9 ~]#

Why Wellington -> Christchurch -> Wellington?

That is where the ~20ms latency has been picked up

Just to be curious I ran a trouceroute to snap.co.nz in Christchurch:
[Fred@fc9 ~]#  traceroute snap.co.nz
traceroute to snap.co.nz (202.37.101.16), 30 hops max, 40 byte packets
 1  10.10.10.10 (10.10.10.10)  0.744 ms  1.647 ms  1.618 ms
 2  192.168.1.1 (192.168.1.1)  6.576 ms  6.561 ms  6.530 ms
 3  p202.124.98.202.snap.net.nz (202.124.98.202)  28.425 ms  32.378 ms  34.378 ms
 4  snap-chc-state2-rtr01.snap.net.nz (202.37.101.254)  35.378 ms  36.269 ms  36.243 ms
 5  vasilli.snap.net.nz (202.37.101.16)  34.256 ms  35.184 ms  35.200 ms
[root@localhost ~]#

Then tried to Auckland:
[Fred@fc9 ~]#  traceroute wxc.co.nz
traceroute to wxc.co.nz (58.28.4.10), 30 hops max, 40 byte packets
 1  10.10.10.10 (10.10.10.10)  0.800 ms  1.744 ms  1.728 ms
 2  192.168.1.1 (192.168.1.1)  6.694 ms  6.691 ms  6.670 ms
 3  p202.124.98.202.snap.net.nz (202.124.98.202)  30.618 ms  34.584 ms  37.563 ms
 4  snap-chc-state2-rtr01.snap.net.nz (202.37.101.254)  38.530 ms  38.515 ms  38.495 ms
 5  snap-akl-telcohse-rtr01.snap.net.nz (202.124.115.34)  50.456 ms  56.415 ms  60.377 ms
 6  wxc1.ape.net.nz (192.203.154.108)  60.379 ms  42.819 ms  50.791 ms
 7  ge-0-0-1-akl-fw01.wxnz.net (58.28.160.2)  56.753 ms  58.725 ms  58.709 ms
 8  umbriel.wxnz.net (58.28.4.10)  58.690 ms  59.638 ms  59.618 ms
[Fred@fc9 ~]# 

Why not straight to the ape from the wellington router?!

Fred