Strange no-one has considered the total drag curve in this thread.
Recall that it starts high at low speed and then reduces to min drag speed from which point up is the only way it goes. I know there may be a little excursion around transonic.
So for a fairly wide range of power settings we have two speeds having equal total drag.
A delta wing has a broad range of speed around min drag where there is little variation so if we use that as an example the effects are magnified.
Assume a flat bottom of the total drag curve over about 30 Kts as with the Vulcan. Now you have a 30 Kt range of speeds at which you can stabilise for a particular power setting.
If you want to cruise within that 30 Kt band of speed then you would be foolish not to accelerate beyond the speed band, set the power and let the speed stabilise back to the high speed end. Otherwise you could be stuck all day at the low end.
Most non deltas will also have a small band of speeds at the bottom of the total drag curve.
So - best method is to hold climb power after levelling, overshoot the expected cruise speed, reduce to cruising power and you should stabilise at the higher value.
Sometimes turbulence or other disturbances will cause you to slip back to the lower speed. More power will be needed for a while to regain the faster speed.
All this is irrelevent if your speeds are further up the total drag curve.