The two hotels are within 50m of each other and together they account for 48 of the alleged 57 hook-ups between an underage prostitute and the 48 men.
The alleged trysts, between September 2010 and February last year, took place at Hotel 81 Bencoolen and Strand Hotel. They are located along Bencoolen Street.
Only eight men used other hotels, such as Shangri-La Hotel and Hotel 81 Lavender.
Such trysts are rare and even more so since the end of last year, said employees at the two hotels.
They cited the ongoing construction in the vicinity to build the Bencoolen Downtown Line 3 station and a change of booking policy at Strand Hotel as the main reasons for the dip.
Madam Safiah Mohammad, 49, who has been running a travel agency near the hotels for two years, said: "Since the construction work began here in October, I have seen fewer (of such) couples.
"Maybe they are put off by the noise."
Mr Hassan Rahman, 49, who frequents the area, agreed. He said: "The construction work must have turned off these men, so they check into other hotels instead."
Ms Lilian Heng, who has been working at the Strand Hotel for 27 years, said her hotel abolished its hourly booking policy last year to deter such couples.
Now, her customers would have to book a room for the entire night - which costs about $189 for a deluxe room.