Personally, I work it as.....
Skink has BS 3. This means.....
Blowpipe single shot, not moved, short range = 4+
Blowpipe single shot, not moved, long range = 5+
Blowpipe single shot, moved, short range = 5+
Blowpipe single shot, moved, long range = 6+
Blowpipe double shot, not moved, short range = 5+
Blowpipe double shot, not moved, long range = 6+
Blowpipe double shot, moved, short range = 6+
Blowpipe double shot, moved, long range = 7+
Javelin, not moved, short range = 4+
Javelin, not moved, long range = 5+
Quick to Fire means...
Javelin, moved, short range = 4+
Javelin, moved, long range = 5+
...so exactly the same for moving as not moving
Add to the fact the Javelin ALWAYS allows stand and shoot due to Quick to Fire, plus you get the shield which bumps the AS to 5+ and grants a 6+ PS as well.
NOTE: Remember that you need to add -1 if firing into Skirmishers as well