c - MPI_Recv: Receiving a different size than the one Sent -

i writing program check shortest path using mpi library. there 2 scenarios:
either found better path, in case first slot of buffer state resultbuff[0] = 1 , need go on rest of contents of buffer better path.
other case resultbuff[0] = 0, , won't excpect values in other cells of buffer.

is possible me use separate mpi_isend calls:

in case found better path , stored in resultbuff[1] resultbuff[10]:

mpi_isend((void*)sendbuff, 11, mpi_int, 0, 1, mpi_comm_world, &request); 

in case didn't found better path:

mpi_isend((void*)sendbuff, 1, mpi_int, 0, 1, mpi_comm_world, &request); 

and in both cases i'll use

mpi_recv( (void*)resultbuff, 11, mpi_int, mpi_any_source, 1, mpi_comm_world, &status); 

to receive result.

will work?
if does, save communication costs if don't send better path?

note: resultbuff of size 11.

yes, can this. mpi standard , man pages mpi_recv, "the count argument indicates maximum length of message; actual number can determined mpi_get_count" call using status object got mpi_recv().

as saving communication costs, won't -- such short messages dominated latency of sending message rather bandwidth.