PT/OT billing - modifier 59

I'm new to PT/OT billing looking for help. When would it be appropriate to bill these therapies/modalities separately with modifier 59? Please note, all of these services are being done on one anatomic area. Example: 97018 with 97140 - 97018 is denying as bundled.. I can find the policy on CCI edits (shown below), but without explanation of when it would be necessary to add modifiers. I understand this edit regarding the timed services, but am confused about this when it's timed and untimed, like the example above. Also - I am not in contact with the providers. Thanks

For example, let’s look at one of the more common codes billed: 97140 (manual therapy techniques like mobilization/manipulation, manual lymphatic drainage, manual traction, on one or more regions, each for 15 minutes). For this code, NCCI states 95851, 95852, 97002, 97004, 97018, 97124, 97530, 97750, and 99186 are all linked services when billed in combination with 97140. So, if you bill any of these codes with 97140, you’ll receive payment for only 97140. Medicare actually uses this example on their site for therapists regarding appropriate use of modifier 59.