"difference was increased" is a correct and usable phrase in written English.
You can use it when describing how something has grown or intensified over a period of time. For example, "The financial difference between the two companies was increased after the acquisition."
The difference was increased slightly by adjustment for change in BMI (β = -0.31, 95% CI -0.51, -0.11).
Alveolar to arterial O2 tension difference was increased significantly in both groups during anesthesia compared to preanesthetic values.
If it failed, the volume difference was increased further (for example from 20 to 30%%) until the subject passed the time interval or failed in all conditions.
sCTX-I was increased 81% in injured VEH mice at day 7, while at day 14 this difference was increased to over 300%.
The glomerular and tubulointerstitial matrix deposition was somewhat increased in 100-day-old ITGA2-/ mice compared with wild-type controls, and this difference was increased further in 150-day-old mice.
If a subject did not pass one of the time intervals, the volume difference was increased (for example from 10to20%0 %), and the subject was tested with the respective time interval.
The price difference was increasing between China and Korea ($9.08; low, $9.82; middle, $10.82; high at quantity of 500 pieces or less).
The price difference was increasing between China and Korea ($9.99; low, $10.56; middle, $11.5; high at the quantity of 500 pieces or less).
As the difference is increased, a point is reached when the two halves of the screen appear differently coloured.
This difference is increased by increasing of the problem size.
With the pressure difference is increased before gas breakthrough is occurred, after which it is sharply decreased.
