I actually had a suit jacket altered a bit since I haven't worn the jacket for a long time somehow I too realized I lost a bit of weight and the tailor was quite precise and was able to get the jacket fit me again. He took about an inch off the waist area so it wouldn't look too bulky. But yes it can be done.
The pants and waist could use some tapering. Bespoke tailors can make modifications but I don't see why it isn't a precise fit considering it does take multiple fittings before finishing a custom made suit.