It is difficult to understand after western backstabbing in Ukraine and Syria still there are delivery issues to please them.It would be some other excuse if not this one so it doesnt matter. Even if there is no border with Iran and labennon unlike Putins transfer of Buk batteries to east ukraine fighters it is impossible for Iran to transfer S300 anywhere else undetected. Still I think it is better to keep all civilian trade agreements and military agreements like tank deal, frigates and so on.As he seems to consider Russian interests as it should be I believe even late Putin will understand where the benefits of Russia will be and stop seeking western approval for at least necessary issues.