Some people like to identify natural weaknesses and then work really, REALLY hard to try to overcome or diminish the effects of those weaknesses. Some people like to identify natural strengths and then work to improve those - basing the argument that there is a higher Return On Investment (ROI) on the time invested to take a good skill/behaviour to great. It is also far more enjoyable, and hence becomes a self-fulfilling cycle of improvement, and naturally diminishes the amount of time spent on doing weaker strength things. Success breeds success, and failure breeds something else.
This is another scaling assessment so I believe mood and environment affect the results. I learned from doing the Myers-Briggs Type Indicator assessment every 3 years or so, that my type shifts around. And this is sensible in my opinion as by knowing yourself better, setting some goals and working on different behaviours and attitudes, it is good to have the long-term confirmation that you are changing!
Possibly this strengthsfinders free online test is similar to a more comprehensive test which comes with a workbook - Strengthsfinder 2.0: A New and Upgraded Edition of the Online Test from Gallup's Now Discover Your Strengths (or co.uk) which sounds great! I have not looked into it.
Give this link to the coachee: RichardStep Strengths and Weaknesses Aptitude Test (RSWAT). Again I think the best time to do the assessment is in the morning, before work really starts.
When the assessment is complete, you will have the "top 5" strengths (again, statistician George EP Box's "all models are wrong, some are useful" applies!). And a list in strength order of the other 29 the test apparently covers. There is some alignment between the MBTI and this RSWAT. And with this test you get a ranking order of 28 small types/aspects of the personality, so useful, in my opinion
You now have material again to either focus coaching goals and plans on making more use of the top 5, or making less use of the bottom 1, or improving skillsets around the bottom. All up to the coachee and your understanding and guidance!