Sorry but that is wrong. It is a common misconception that the charging current will divide equally between 2 batteries in parallel which creates the misunderstanding that the weaker one will be overcharged before the better one gets fully charged. However you can even charge batteries of radically different sizes because the current divides in proportion to their capacity so both charge at the same rate and reach full charge at the same time.
When charging in series where the current is identical in each battery your argument is valid but it doesn't apply to parallel operation. Due to frequent misunderstanding of the difference between parallel and series, the rules for matching gets applied mistakenly to parallel.
You don't say what industry is having problems in your experience but I've worked in telephone exchanges with a 2,500 sq ft room full of backup batteries in parallel on standby float. It is standard practice for off-the-grid solar systems.