The difficulty is exactly what you would expect on the real GMAT since these are official GMAT retired questions. These questions have appeared in real GMAT questions. You'd receive a score in GMAT based on the difficulty level of the questions you answer correctly and wrongly.
The Verbal review has questions of all difficulty levels and depending on what your level is your time taken on those questions may be more or less than what you would actually be spending on questions of your difficulty level. For an example, if your level is 600 and you solve all 500 questions then you would be doing them quickly and with a higher accuracy than you'd when you'd be doing the 700 level questions.
Hence, the way you are trying to assess your current level is not right. Try to solve questions from adaptive sources such as mocks from
MGMAT, Veritas, sholaranium from
EGMAT, etc.