"differences in extent" is correct and usable in written English.
You can use it to describe different degrees of something, such as differences in the extent of a damage or the differences in extent of a certain skill. For example, "The differences in extent of knowledge between the students was quite remarkable."
The differences in extent of mobility of polymers between different starch types can potentially illuminate differences in starch structure and architecture.
The differences in the cytokine profiles in lymphoproliferation reactions under different co-culture conditions could account for the differences in extent of immune-suppression observed with primed BMMSCs and WJMSCs.
These differences in extent were due to small scale differences in morphology and extreme water repellency.
No significant differences in extent of absorption due to changes in extent of release were predicted or observed.
They were compared with patients who were not taking platelet-altering medicines to assess differences in extent of blood loss.
There were no significant differences in extent of the mandibular retrognathia or magnitude of change between the two groups.
"There's definitely differences in extents to which people care about other people think," Niven explains.
Node status, which could have indicated a difference in extent of disease spread, was not significantly different either, although 95% CI were well within the estimates from national studies [ 18, 31].
The difference in extent of dermomyotome restoration anterior to the segmentation rescue in different heat shock stages may be explained by different rates of cell maturation along anterior-posterior axis.
The effect could not be explained for by the difference in extent of resection in either temporal lobe.
There was a large difference in extent just for two species, one timber and one palm, and a reduction in the predicted area for one species, Swietenia macrophylla.
