Plus VS Buisness

A user is considering switching from ChatGPT Plus to Business, primarily for access to "Sol Extra High." They currently use "GPT-5.6 Sol High" on Plus for document analysis, spreadsheets, and file creation without hitting usage limits, though "Codex" limits are more noticeable. The user wants to know if they can realistically use "Sol Extra High" as their default model on Business, similar to their current use of "Sol High" on Plus.