Project with multiple quizzes submitting an incorrect score when the score can only improve setting is applied

Ok, so we are currently working on a project that is split into different job roles.

It requires separate question banks for each job role and then another question bank that has questions for all job roles and ties in the scores from the individual job role related quiz banks by using dummy questions marked correct based upon variables in the first question banks. 

So for example the user does the 5 questions in their job roles question bank gets 4/5. This sets a variable to 4. User then goes on to the main set of questions with 5 questions for all roles and 5 dummy questions. These dummy questions are marked correct or incorrect based on the score of the variable so in this example 4/5 dummy questions are marked correct and the score from these 5 dummy questions and the 5 questions for all roles makes up the results slide.

It looks like this: http://imgur.com/v9fQqmX

With a results slide at the bottom which is what we have selected the tracking to be based on.

Now this all works fine when the setting SCORE_CAN_ONLY_IMPROVE is set to false in the configuration.js file. Yet the client requires it to be set so that only the best score is kept if the user wishes to retry the quiz. Unfortunately when this is set to true the reporting gets confused and starts sending back scores that are very different to what is on the results slide. 

Have tested on their LMS and SCORM cloud to the same result.

Unfortunately the LMS does not have a score can only improve setting at their end. So is there any other way to make sure the score sent to the LMS is the right one ie. the score from the results slide?