I was experimenting with nether tempest (despite its 250% PvP buff, it ticks for 2.1k, dealt 60k damage over 12 seconds! WOW!), and then I remembered that Living Bomb was also buffed by 444%.
I went to try it.
PvE UI: 11,187 damage over 3.4 seconds and explode for 6,154 damage. PvP UI: 61,999 damage over 3.4 seconds and explode for 37,192 (Numbers fluctuate every second on the UI, closest numbers I could get).
It probably needs to be tested against an actual player, and my mage is only level 54. All I can do is explain the tooltip to be accurate, which should be a 4x multiplier on the dot and a 4.44x multiplier on the explosion. The rest of the difference is just gear, and probably things like incanter’s flow, flame cannon, etc, that can fluctuate and influence the tooltip