HI it sounds like a reflux flaire up to me to. You wil find alot of refluxes seem to have a flaire up around th 4 to 6 month mark for some reason, sometimes its teething that can cause a fliar up it may sound silly i know but if they teeting and producing and swalowing saliva that can be ehough to cause a flair in these bubs
It does sound like the losec dose is farly low, and also Was you meaning its compounded at 5mg per ml if so i would also be ccocerned as to weather that is taying stable ehough, fro what i have learnt the most stable mix is 2mg per ml, and its also a good idea to get it compuned fortnightly

Whist bubs is having a bad patch you could try useing gastrogel or mylanta as a break through leeping in mind not to give it one hour either side of the losec

Before altering any meds though i would sugest discusing with the pead

good luck

Reflux sucks