We often get questions regarding cash vs accrual accounting during the quickbooks import process. The method of accounting, cash vs. accrual, is a reporting exercise in Quickbooks. However PlanGuru relies on a "report" generated by Quickbooks to import data, thus your default report settings may be impacting how the information gets pulled into PlanGuru.
To set your default report settings in Quickbooks take these steps. Open up the Quickbooks company of interest and go to Edit>Preferences, and once in the preferences menu select Reports and Graphs and change the default option on the Company Preferences tab (see the Radio buttons under "Summary Report Basis" header).