Mr. lybrate-user , Thanks for the query.
When on treatment it is essential that TSH is maintained < 3 mU/L, to be free from all the symptoms of hypothyroidism. Since her TSH is 6.05 mU/L, the symptoms are bound to come back. Therefore, it is necessary to to increase the dose of Levothyroxine
initially by 12.5 mcg per day, then check TSH after 6 weeks, if the desired level is attained, then continue the same dose. If not then it may have to be increased further by similar quantity. If you have any doubts please do come back. Thanks.