It has the same possibility of delay that any first class letter would. Preparation time takes longer but delivery time doesn't. Postal Processing High speed machines read your address today. The machine sorts 60 letters per second. If the machine can't read it, it goes to the manual reader to be read by a person who sits all day typing in zip codes at one per second.
Appearances are important.
Uniformly aligned on left margin Clear and sharp without touching or overlapping characters. Clearly visible in windowed envelopes, even when insert shifts. Foreign Addressing International addresses are done the same way except that the country must appear on the last line in all capital letters in English.