Janus' numbers

From his passive, his threshold debuff, and distance scaling, Janus' "Through Space and Time" can reach a total of 285% scaling, which gives it the theoretical highest possible damage in the game from a single non-DoT ability. Essentially this was an experiment to get the largest number possible.

Using the same build found here: http://pastebin.com/MVspgYWK , Janus reaches 1698 magical power. In theory, with 600 base damage and 285% scaling, that ult at max range would hit for 5439.3 damage before protections. In the experiments run, the target (sobek) had 48 magical protection, the damage should in theory be reported as 3675.2 (The game would display this damage as one tick of 2295, one tick of 286, and one tick of 773).

In our first test, I had forgotten to activate Girdle, resulting in no penetration and only 1519 power. With 600+285%, this should have dealt 4929.15 before protections, and 3330.5 after sobek's 48. However, from the damage recap, we see that Janus dealt a total of 3843 damage after protections, meaning Janus was dealing 5687.64 damage before protections. Getting rid of the base 600, it means 5087.64 was from scaled magical power, or 334%.
Janus' perspective - http://a.pomf.se/mrioqx.webm
Sobek's perspective - http://a.pomf.se/erszmt.webm
Sobek's damage recap - http://i.imgur.com/su0KkLe.png

In subsequent tests, I had neglected to activate Janus' passive, but remembering the girdle. This mean I had 1698 power, 10% magical penetration, but (theoretically) 260% scaling. However, our test returned a total damage of 4094, which after protections and penetration, puts the raw damage at 5862.608. Getting rid of the 600 base, that puts the damage from scaling at 5262.608, or 309.9%.
Janus' perspective - http://a.pomf.se/nphbwo.webm
Sobek's perspective - http://a.pomf.se/otlfgh.webm

It was at this point I realized I was probably doing the math wrong. I mean damage doesn't just come out of thin air. The wording of Janus' ult states that it gains "up to 200%", as opposed to "an additional 200%". However, if you look at his ult's base scaling at max range as 250% and not 200%, it means that in our first test, it puts the scaling at 335% and in the second test at 310%, which matches the value found.

So finally, if I wasn't an idiot, and I had remembered to activate both girdle and Janus' passive, it would make the total possible damage from Janus' ult 600 + 335% of 1698, for a grand possible total of 6288.3
And here it is tested:
Janus' perspective - http://a.pomf.se/kpwcrt.webm
Sobek's perspective -http://a.pomf.se/nfpwhh.webm
Sobek's damage report - http://imgur.com/mKTydAM
3383+711+296 damage, which on a target with 48 protections and 10% penetration means it was dealing 6286.48 raw damage, subtract the base of 600 is 5686.48, which is 334.89% of 1698 magical power.