"although there were differences" is correct and usable in written English.
It can be used to express contrast or to make a comparison between two things, showing that despite any differences, something else is true. For example, "Although there were differences in their opinions, they both agreed to move ahead with the project."
Very few respondents thought that publication of these data was totally unacceptable and useless although there were differences between scores for different data items.
Preference patterns were consistent across different population subgroups, although there were differences in relative strength of preferences.
Although there were differences in overall survival among the different subgroups, these did not reach statistical significance (P = 0.06).
Noticeably, postoperative BCVA did not differ between the two groups, although there were differences in ECC, CCT and macular thickness.
Although there were differences in the quantities of bound ketoprofen within the different layers of the skin, these levels did not appear to correlate with irradiation time.
Although there were differences between these theorists, they shared certain common assumptions.
The report also said that labor markets improved modestly across the country, although there were differences in the types of jobs.
On the future level of Dutch activities in Afghanistan, FM Verhagen noted PM Balkenende had made clear in his morning meeting with President Obama that although there were differences within the Dutch coalition government that were still being worked out, he was convinced the Dutch would stay in some capacity in Afghanistan and continue to build on their experience with the 3D approach.
Although there were differences in the shape of the titration curves, the normalized curves showed that humic acids of different sources can exhibit common similarities.
Although there were differences between the three countries involved in the study, findings suggest that key stressors are mainly associated with socio-economic and governance issues.
Although there were differences compared with the present-day coastal management, it was already more advanced than the management systems merely based on custom, taboos and cultural norms.
