Long by chron is preffered in morning because:
1) It is easier to get longitude at noon with correction no need of plotting.
2) Accuracy of fix increased with PL observed with Long by Chron the angle of cut is as close to 90°,
3) In morning the altitude is changing quite fast as compared to Azimuth and in the formula of intercept, this fast change of altitude can cause error in calculation of TZD and hence error in intercept whereas in the long by chron the true Altitude is in numerator so a small error does not affect the accuracy of fix a lot.
Ref: Seaman guide Website
