James Miller. There's no further extensions after September 30, so even if the OP entered now, he would only just get the 3x90. He's talking about coming in May which might mean he'll get only 2x90.
James Miller. There is no Embassy in The Maldives. Residents must go through the Colombo Embassy in Sri Lanka for visas. There is only an Hon Consulate in Maldives. There was a post in another group relating to this.
Abdul Rehman Ahmad. May is ok, bit you'll only be able to get the one extension, so you'll get 2x90 instead of 3x90. The M/E TR visa gives you 60+30, with a potential further 60+30 if you leave and re-enter
STV is losing its value. If you enter after July 3 you get only 90 days (non-extendable) and no further extension available after September 30. Best to consider standard ME Tourist Visa
Tod Daniels. If applying at an immigration office, do you have to use your regular office, or can you just rock up at any IO and get a re-entry permit?
Which country are you from? Depending on that you have either (a) affidavit from your embassy certifying pension payments in your home country, or (b) 12 monthly international transfers into a Thai bank account.