We don't have 4.5 hr min day credit, we have 4.5 hr min duty credit:
Trip starts Thursday 24th, ends Sunday 27th (early AM), so takes up 4 calendar days, pays 3x4.5=13.5 hr credit.

Pairing # L4272 : 24MAY

L4272 : 24MAY ONLY ON THU BSE REPT: 2300L Operates: May 24 Only
Base/Equip: LAS/321 CA01FO01
DY DD DH C FLTNO DPS-ARS DEPL ARRL BLKT GRNT OA EQP TBLK TDHD TCRD TDUTY/FDP LAYOVER
TH 24 696 LAS-BWI 2345 0718 0433 320 0433 0433 0548/0518 BWI 1326
D-END: 0748L (NR 900) REPT: 2114L HYATT PLACE BALTIMORE AIR 410-859-3366
FR 25 369 BWI-ORD 2159 2309 0210 320 0210 0210 0325/0255 ORD 1850
D-END: 2339L (NR 900) REPT: 1829L DOUBLETREE OHARE ROSEMONT 847-292-9100
SA 26 * 295 ORD-IAH 1914 2205 0251 0054 320
SA 26 199 IAH-LAS 2259 0010 0311 320 0602 0602 0811/0741
D-END: 0040L T.A.F.B.: 4940 TRIP RIG: 0045
Total: 1245 0000 1330 1724/1554

EDIT: just saw question has been answered already, here is a sample trip, sorry for formatting..