Hi Folks,
I have checked my database out for both registrations and noted the following;
The registration N400SP has not been used at all from 1987 - which as far back as I can go through official copies of the FAA database.
The history of N4005P is as follows;
mysql> select reg_no, mfr_name, model, con_no, owner, faadate from jos_av_scrape, jos_av_type where type_key=type_id and reg_no="N4005P" order by faadate;
+--------+-------------------+-------+--------+--------------------------------+------------+
| reg_no | mfr_name | model | con_no | owner | faadate |
+--------+-------------------+-------+--------+--------------------------------+------------+
| N4005P | AYRES CORPORATION | S-2R | 2496R | NEWPORT FLYING SERVICE INC | 2003-07-07 |
| N4005P | AYRES CORPORATION | S-2R | 2496R | MCCONNAUGHHAY KEN | 2004-02-09 |
| N4005P | AYRES CORPORATION | S-2R | 2496R | TRIPP AG INC | 2006-02-06 |
| N4005P | AYRES CORPORATION | S-2R | 2496R | STEVEN REID FLYING SERVICE LLC | 2010-04-02 |
| N4005P | AYRES CORPORATION | S-2R | 2496R | CROOM LEON D II | 2011-12-02 |
| N4005P | AYRES CORPORATION | S-2R | 2496R | REGISTRATION PENDING | 2012-06-01 |
| N4005P | AYRES CORPORATION | S-2R | 2496R | CRYSTAL VALLEY COOPERATIVE | 2012-06-08 |
+--------+-------------------+-------+--------+--------------------------------+------------+
7 rows in set (0.00 sec)
It looks like it may have been rebuilt and re registered, hope that this helps.