Actually you can see effect just by setting experience level and then clicking back to briefing, returning to setting has experience revert while time setting adjustments stay.

Time setting and end on force morale too low seem to be able to be changed and show their effects, on same new game as one where experience did not take effect change form elite to line had no apparent impact on forces, and when reopening save file settings were at elite again.

When I play operations and set the experience level it always reverts to Elite. This is clear when I return to a saved game because I can see settings. It seems likeky that effect is immediate since each op I start all the "squads" have 2-4 men, usually 2-3 despite settings being on line.