A PA-31T SALESMAN; DEMONSTRATING HIS ACFT FOR A CUSTOMER; OVERSHOT HIS ASSIGNED ALT.

Narrative

THIS WAS A DEMO FLT FOR PROSPECTIVE NEW OWNER AND HIS ATP PLT FROM RMG TO ORL AND RETURN TO RMG. I FLEW THIS ACFT AS SINGLE PLT FOR APPROX 3 YRS; BUT ONLY OCCASIONALLY FOR LAST YR. OFF RMG; WE WERE CLRED 10000 FT; HDG 200 DEGS. AT 8000 FT; WE WERE CLRED TO 12000 FT. SET 12000 FT IN ALT ALERT. WE WERE CLBING APPROX 2500 FPM ON AUTOPLT. OTHER PLT (FIRST TIME IN CHEYENNE) ASKED QUESTION ABOUT FLT DIRECTOR. AS I WAS ANSWERING HIS QUESTION; ATC ASKED MY ALT. I LOOKED AND WAS APCHING 13000 FT. MY ANSWER WAS 'CORRECTING TO 12000 FT;' AND DID SO. CONTRIBUTING FACTORS WERE THE FACT THAT THE ALT ALERT DID NOT BEEP AND THE FACT THAT I WAS DIVERTING ATTN TO THE OTHER PLT'S UNDERSTANDING THE FLT DIRECTOR WHEN I SHOULD HAVE BEEN WATCHING THE ALT. ANOTHER CONTRIBUTING FACTOR WAS I NOW FLY A BE200B WITH EFIS. THE SYS WILL CAPTURE THE ALT SELECTED IN THE ALERTER. ALSO; THE CHEYENNE II CLBS FASTER THAN THE KING AIR. THIS ERROR WAS DISCOVERED BY ATC AND I CORRECTED BACK TO CORRECT ALT IN A FEW SECONDS. APPROX 2 MINS LATER; I WAS GIVEN FL230 AND ON COURSE WITH NO PROBS. IT WAS VMC. NO OTHER ACFT.