asterisk users - Jul 2015 - Dial L options and attended tranfer

Hello guys,

there is something i'm not sure and would like to ask please :

let's say i have B calling and talking to A.    (  A  <------>   B  )
Then B would like to attended transfer A to C.
In the behind extensions.conf when B is calling C (first part of the 
attended transfer) the Dial application is called
with the L(x,y,z) options.   (  B  <---------> C )

Then B hangup and C is talking to A.  ( A  <-------> C )

my questions are :
1) Is the limit of the call and time to play warning are calculated when 
the Dial begins (1st part of the attended transfer) (  B <---------> C ) ?
2) if yes is there a way to make the calculation begin when the transfer 
is completed ( A  <-------> C ) ?


thanks a lot,

regards,


Alan