HAL does not offer any form of 55+ rates, neither does Princess. They do offer military rates but do not publish them, the T/A has to call and ask for them, not use the booking engine. The one big difference in their military rates frome the traditional way of offering them is they only apply to active duty personell. Vets are out of luck with HAL. They do also offer, a rate as previously posted for "Community Appreciation" that applies to teachers, firefighters and police officers.
None of their promotional rate are as good as their Flash and SWAT promos that are run frequently but typically last minute and short term on sailings they are having trouble filling. Again, they do not always make these rate readily available to all agencies. They are, unlike the military rates, shown on the booking engines for very large (usually internet based) agencies. When they run these, it'll be the lowest rates you'll ever see on HAL, below past pax promos, mil and even community apprec. rates.
If you see a HAL rate that looks too good to be true, it is one of these rates. They typically have very different booking rules associated with them. Payment in full is required no matter how far out you book. They go into 100% penalty the day you book your cruise so please buy insurance if you book one of these or you'll loose every dollar for cancellation.
They do have great promotions, they are just different from CCL or PCL or the other lines in the Carnival Corp family. With HAL, a good agent at one of the large agencies can sometimes find rates well below what you'll find elsewhere, even booking direct. Certainly not always the case but when shopping for HAL shop around. They reward the agencies with a reputation for filling their ships with promos you can't always find elsewhere.