The answer to your question is NO, the tongue weight will not change. In your example you would still have 12% tongue weight. The amount of weight felt by the tow vehicle will change but the actual tongue weight, and therefor the percent of tongue weight to total trailer weight, does not change nor does the tendency of the the trailer to sway due to tongue weight and balance change.
The only way to change the above would be to move the axles, load or move stuff in front of or behind the axles, or lengthen the tongue.
See the sticky at the top of this forum for more information.
Hope this helps.
Barney