OK465 I think you misunderstood my point.
You are correct it will not accelerate to 250 KIAS, I did not state so.
What I stated was that if (for instance by ATC leaving you too high) VNAV is above VNAV PTH trajectory and above the speed limit FL is accelerating to regain the PTH, crossing the speed limit level it will level off, bleed off its speed to 240+10 maximum and then attempt to further regain its PTH while maintaining maximum 240+10..
The 240/100 serves as a speed restriction, with -15/+10kts allowance.
Any speed restriction coded after this point will be obeyed from that point onwards.
Including 220/ but also 220B/ thus allowing the airframe to reduce below 220 without forcing it to maintain it until after such point.