The labor for a bearing repack and a bearing replace are going to be DIFFERENT if the tech is doing the job correctly. Bearing replacement is accompanied by bearing race replacement. Replacing a race isn't rocket science, but the person doing it should know what they're doing.
Repacking does not involve race replacement. The book says to use a dial indicator to set bearing preload. There was a recent discussion of this point and like other discussions here, some believe you need to set preload with a dial indicator; some say not.
I don't know what type of facility you had your oil changed at, but I'd seek another opinion. Find a shop versed in MBs.
A siezed wheel bearing can cause grief to include damage not only to your car, but to your own well-being. I wouldn't put this off.
1991 300-SEL - Model 126
M103 - SOHC
James Madison - Oppressors can tyrannize only when they achieve a standing army, an enslaved press, and a disarmed populace.
Liberty Firearms Training - After years of trying to regulate California criminals with a never ending stream of gun control laws they have still not given up with the belief that if they make something a crime that criminals will miraculously start obeying the law.