sitter pickup time has slid from 11pm to 2am over a year and shes started "joking" about it

F37 dh 39, two kids 4 and 6, sitter is a 28yo woman weve had for almost 14 months. she lives w a flatmate maybe 15 mins from us, gets her own uber home which we pay for, very flexible w late pickup times bc shes a night owl and works freelance and sleeps in on sundays. all great. issue is. when we started using her we'd told her we'd be back by 11pm. that was generous, gave us time for dinner and a drink. within 3 months we were back by 11.45. within 6 months it was 12.30. weve now hit roughly a year of monthly club nights and we are routinely walking back in between 1.30 and 2am. shes never said no, she charges us properly for the extra time, she gets her uber home, all gravy. but. the last 3 weekends shes made what i think are deliberately light "jokes" abt the situation. "you guys really know how to party". "haha must have been some restaurant if it kept you out til 1am". "you and dh on a school night again??" (last time was a fri, kids dont have school sat, but the implication was funny). all delivered totally warmly, no edge to her tone. but theyre piling up. i cant tell if shes genuinely just making chitchat and im paranoid, or maybe signalling that she has worked it out and wants us to know she has worked it out, or maybe building up to actually asking a more pointed question, or honestly just preparing to renegotiate her rate bc shes realised she could ask more. dh thinks its d, i think its more b. neither of us has the guts to actually clarify. am i overthinking the "joke" pattern. is this a thing other ppl have hit. and if she IS hinting that she "knows", what is the polite thing to do about that.