Alternatively, you can take advantage of Maples ability to handle equations.
In the attached example, no assignment statements “:=” are used for parameters. Instead, general analytic solutions are derived and parameters for a particular solution are defined as equations (as you would write it by hand).
Using this workstyle, no re-execution of the whole worksheet is required when parameters are changed. This is an advantage if the worksheet becomes large or if parameter studies are done. Also, numerical artifacts or missmatch of units, as in your case, are less likely to impact calculations and results.
Maple Worksheet - Error
Failed to load the worksheet /maplenet/convert/Answer_on_-_Solving_equation_with_units_problem.mw .