Hi, my rheumatologist increased my folic acid from 5mg once a week, to 10mg once a week to prevent it upsetting my gut. It was later increased to 5mg six times a week after my hairdresser commented on more than usual hair falling out when she washed it (after the mtx was increased from 15mg to 20mg each week). So 3mg six times a week doesn't sound problematic to me and there is scope to increase it further if needed. It's just a vitamin that gets depleted by the mtx, and the deficiency causes symptoms, so replacing the vitamin seems logical.
Peripheral and axial AS diagnosed October 2011 aged 50, more than 15 years after the symptoms started. Also PCOS, GERD/oesophagitis/dysphagia, IBS, asthma,chronic rhinitis. Taking enbrel, methotrexate, folic acid, omeprazole, vitamin D, metformin, steroid inhaler and eating low starch/low GI.