A new auditor is assigned to the allowance for doubtful accounts and

perform the analytical procedures detailed in the chart. There have been no significant changes during the year in either the client’s credit policies or customer base. Are there any auditing concerns about adjusting the allowance for doubtful accounts based on the information shown below?
2018                           2017                           2016
Client/Industry           Client/Industry           Client/Industry
Allowance/AR                                   8.3/7.2                       8.5/7.4                       8.3/7.4
Days AR Outstanding                       32.4/23.8                    28.6/25.1                    28.3/24.7