No, its a good set of questions and this Forum is okay for it since it deals with a very historic hurricane. First, here is an extract from the NHC bulletins:

"14 16.80 -82.10 10/19/03Z 95 945 HURRICANE-2
15 16.90 -82.00 10/19/05Z 130 901 HURRICANE-4
15A 17.00 -82.20 10/19/06Z 130 901 HURRICANE-4
16 17.20 -82.50 10/19/09Z 150 884 HURRICANE-5
16A 17.20 -82.80 10/19/12Z 150 882 HURRICANE-5
17 17.40 -83.20 10/19/15Z 150 882 HURRICANE-5
17A 17.50 -83.50 10/19/18Z 145 900 HURRICANE-5
18 17.70 -83.70 10/19/21Z 140 892 HURRICANE-5
18A 17.90 -83.90 10/20/00Z 140 892 HURRICANE-5
19 18.10 -84.30 10/20/03Z 135 894 HURRICANE-4
19A 18.10 -84.70 10/20/06Z 135 899 HURRICANE-4
20 18.30 -85.00 10/20/09Z 130 900 HURRICANE-4
20A 18.30 -85.20 10/20/12Z 125 910 HURRICANE-4"

At 0800Z, recon reported a central pressure of 884MB - and this was the value that was used in the bulletin at 09Z. When the aircraft landed the calibrated value was confirmed to be 882MB and this value was used in the bulletins at 12Z and 15Z. At 18Z, the NHC bulletin estimated pressure at 900MB and at 1806Z, recon reported a value of 894MB, so it is quite likely that almost immediately after 15Z the pressure began to rise. The period of record for 882MB is 08Z to 15Z - a total of 7 hours, but at 1615Z the pressure would have already been on the increase. Notice the pressure drop of 44MB in two hours from 03Z to 05Z - quite remarkable!
ED