Yeah as said the Petronas medical is pretty standard, I did mine in Johur last year and was in & out within 30mins.
The LPS is a full day course. When we did that in March it was taking around 3 days after to get clearance before you could enter the field.
Another requirement for Exxon is that you have done the TSBB (travel safely by boat course) some people get this as part of the survival course and others do not, they have to attend a half day course that actually just took 40 minutes!
Which field you heading out to? Tapis has big re-generation project going on at the moment expected to run through into next year, several vessels & barges are there with ROV & dive spreads.