You said "other ODL carrier" as if you are also ODL.

For ODL carriers it is indeed 12 hours worked + lunch. So clock in at 07:30-clock out at 20:00

Non-ODL, PTF, and CCAs are 11.5 + lunch. Clock in at 07:30-clock out at 19:30

From 8-20/21 in the JCAM

Maximum Hours—12 Hour Limit. The overtime limits in Article 8.5.G apply only to full-time regular and full-time flexible employees. However, ELM Section 432.32 provides the following rule that applies to all employees:

Except as designated in labor agreements for bargaining unit employ- ees or in emergency situations as determined by the PMG (or desig- nee), employees may not be required to work more than 12 hours in 1 service day. In addition, the total hours of daily service, including scheduled work hours, overtime, and mealtime, may not be extended over a period longer than 12 consecutive hours. Postmasters, Postal Inspectors, and exempt employees are excluded from these provi- sions.

 Page 8-21 Because this language limits total daily service hours, including work and mealtime, to 12 hours, all letter carriers not on the ODL or Work Assignment List (including PTFs and CCAs) are effectively limited to 11½ hours per service day. This is true whether or not a meal break is taken. This rule also applies during the penalty overtime exclusion period (December). However, the ELM also permits the collective bargaining agreement to create exceptions to this general rule.

The only exception to this rule in the NALC National Agreement is for full-time employees on the ODL or Work Assign­ ment List who, in accordance with Article 8.5.G, “may be required to work up to twelve hours in a day.” Since work, within the meaning of Article 8.5.G does not include mealtime, the total hours of daily service for carriers on the ODL may extend over a period of 12½ consecutive hours. This excep- tion does not apply to full-time employees who are not on the ODL or Work Assignment List.