SBS9818A SG IMO, recreational services like Sv. 401 and Sv. 354 have very messy timetabling. It's hard to strike a balance, really.
freakybuses SG 403 is rather balanced... not sure about 400 as I always take without others on board... maybe slight unbalance...
gynobcard SG 400 freq IMO is only regular on weekends and fridays coz that's when the crowd descends on Marina South. don't forget they have 400A to supplement the load on 400 too.