When Doolittle took over the 8th AF from Eaker in early 1944 he changed the role of the escort fighters - instead of close escort they were instructed to engage and destroy the Luftwaffe. To that end the routes taken by the bombers to target no longer contained diversionary tactics and they flew more directly to the target. The bombers became the bait, but they still had important missions to accomplish.
And the fighters were still assigned to 'close' escort. What changed was that fighters, when they spotted LW, engaged and pursued - rather than drive them off and return. The Fighter Groups however were not homogeneous in leadership. The 4th and 357th and 352nd were perhaps the 'most aggressive' with the 356th at the other end of the spectrum and the rest of the Groups falling in between. The 'Tweeners' like the 355th were parsimonious about sending forces to engage and pursue but favored leaving most of the escort force in proximity, or filling in behind the 4th for example, in a fight which drew most of their fighters away.
If the Luftwaffe didn't come to fight then the escorts were encouraged to go find them and destroy them on the ground, or otherwise destroy targets of opportunity.
True - but they left their escort duties only when relieved by another fighter group - then they went home at medium altitude until they spotted something worthwhile, like an airfield.
The initial results of the new tactics didn't change the number of losses of the 8th AF much, but it did have a greater effect on the losses of the Luftwaffe.