Potty training sitting on toilet for 75% of session???

My BCBA wants us to have our kiddo sit on the toilet for 45 mins then be free and around with no SD or work for 15 for a full 8 hours meaning that our kiddo will be on the toilet for 6/8 hour they are here. Ik this can cause hemerroids and just bad for health overall. How do I confront this.