Gaps "..." in ASME Sec II Part D allowables

[ashim2004]

I would like to know why there are gaps "..." in code allowables. For example for SA 516 Gr 70, allowables not available at 250F even though if we interpolate between 200F and 300F, it results in 20ksi.
Thanks,
Ashim.

 

[metengr]

the "...." means not reported.