Some improvements are made:
Suppose Upper Threshold to convert to scientific notation is 6. In the past, 1000000 displays as 1000000, while 2000000 displays as 2E6. In Origin 2018b, 2000000 will still display as 2000000. Only values equal or bigger than 1E7 will convert to scientific notation.
There was some round off error in the past. To see the problem: Suppose Lower Threshold Power to convert to scientific notation is -3. In the past if the axis is from 0.001 on 10, it will display as 0.001 fine. If axis is from 10 to 0.001 (axis decreases), 0.001 showed as 1E-3. Fixed in Origin 2018b now. Shows 0.001.