Castle Cary postal rate puzzle

I cannot understand the postal rate for the entire shown below.  The entire seems to have gone from Castle Cary to Shaftesbury by the Shaftesbury Fifth Clause Post yet is charged 5d (initial charge was 4d which was then crossed out and replaced by 5d).  The entire is a single sheet and does not appear to have any enclosures.
Why was it charged 5d ?

In contrast the entire here is charged 6d appropriately - 5d for 15-20 miles from Shaftesbury to Sherbourne plus 1d for the Fifth Clause Post (although strictly speaking the sender should have paid for the 5th Clause Post).