450 is 45% of 1000 (the standard X1 tick, before everything got doubled), which means that what you both said is correct, and the same thing. Currently with an X1 multiplier you get 2000 xp at gen 1. At gen 2 you get 2060 xp, which is a 3% increase. At gen 16 you would instead get 2900 xp per tick, which is a 3*15 = 45% increase (the max possible xp increase).
That said, if you want to go to higher levels, I would recommend getting a higher gen bonus beforehand. However, if you would rather have more loompoints, then it is more beneficial to go from level 35 to 36 since you maintain a higher level for longer, instead of having to start back at level 1 and grinding your way up to 35 three times.