I have a valid c-type visa, multiple, 30 days, validity: 2/10/2014 - 2/1/2015 which I'd use this October for 12 days.
I plan to travel again entering Schengen 10/12/2014 and exit on 2/1/2015 . total 24 days.
Coincidentally, my current visa will still be valid until the day I exit Schengen. however I would have overstay the maximum 30 days stay of the visa.
TLS advise me to apply for a new visa, for the December trip to whichever is my main destination embassy. however, they are unclear of issuing the December visa if it is possible given old visa is still valid but not enough remaining days of stay?