Magnitude - 1. The great size or extent of something; great importance. 2. Size. 3. The degree of brightness of a star.
- via Google
It more than likely means size.
The order you apply the adjustments does make a difference because the percents that are applied will be applied to different amount.
For example, 80% of 100 = $80. The price would be $180.
Decreasing this by 25% 25% of 180 = $45; 180-45 = $135.
25% of 100 is not the same as 25% of 180.
