What's the difference between since + present perfect and since + past simple when since is not used as because?
I've seen both being used but never really understood what's the difference -between these two for example
I've been a different person since I've gone to Spain
I've been a different person since I went to Spain
or
The department has been extremely busy since we have had/opened an office in Mumbai.
The department has been extremely busy since we opened an office in Mumbai.