Clearing immigration and customs and then bus to domestic terminal normally takes under 60 min. A few days per year it can take several hours (mostly due to strikes by immigration workers who have been without a contract for circa 3 years now). The risk is MH flight being delayed by 2 hours, which has gotten more common as MH decommisions aircraft and runs with few spare planes or crews as part of their downsizing. Later flight isn't much safer, you'd have to book travel to PER the next day to be reasonably safe. Sad to see how MH has fallen, but understandable.