when i first tested deficient, my level was down in the 50s and my doc said 100mg per day for a month. just as an FYI, at first i took it all in one go and it made me feel sick. better to split it up.
also zinc levels are naturally highest in morning, so i try to take any zinc supplements early in the day.
your wife could try 50mg in the morning and 50mg midmorning or before lunch for 2 weeks, then drop back to 50mg in the morning for 2 more weeks, then retest.
IMPORTANT: ensure the zinc product is blended with 2-3mg of copper.
(bad, bad lab.. ugh)