Depreciation expense as a proportion of asset size

In the topic of evaluating quality of financial reports, the step in the analysis of expense recognition practice mentions a point “compare depreciation expense as a proportion of asset size over time and with peers”.

My question is that high or low depreciation expense as a proportion of asset size will indicate earning manipulation?

thanks

Could be either.

Unusually high depreciation to show lower income and pay less in income tax, perhaps, or unusually low depreciation to show higher income and pay bigger management bonuses, perhaps.