You have answwered your question why you looking at changing the system if you are getting the grades.
You find your approach time consuming and difficult.
You know when you learn something new there is a learning curve. That applies to PhotoReading as well so when you learn PhotoReading be sure you know how it workd before you apply it to your school work. Then there is no reason for dropping in the grade. One of the reason people allow their grades to decline when they take up PhotoReading is because they are learning PhotoReading to quit working on studying period. It's not a conscious choice, we often reach that point when we've had enough with something and start looking for a way out. Sometimes we need to consider the 80/20 rule. If 20% of your effort will give you an 80% grade is it really worth the added 80% effort to keep the grade at 95%? 80% is a good passing grade and keeps you human. That is not to say that 95% cannot be achieved with PhotoReading but lets be fair... we come to PhotoReading because we want to have more free time than doing our home work all the time.
If you work hard at it to achieve A's then you need to expect to put in some effort using the PhotoReading system It sill mean you'll be able to reduce your study time to 1/3 it takes you now to get the same or better results. However first learn the system away from your studies. Something that many don't have the patience to do so it does cost them in their grade. Once you know how the system works you apply it to your studies. You know what it takes to achieve A's now You work the PhotoReading system to get you there.
Alex