The towing capacity of your hitch is 10k. ( Total trailer weight)
What is the listed tongue weight rating; there should be two numbers listed, with and without equalizers; if you're using your trailer, without equalizers , and that, weight rating is, 2k then cutting that in half, gives only 1,000 lbs. Then your trailer tongue weight of 1,200 lbs. is over weight.
Most manufacturers of the extenders , say not to use them with equalizer hitches.
Right now , given the numbers you've posted, not enough info, to say if you have a safe set up.