The time limits are controlled at the user group level within Pharos, and the environment assigned to those groups does not impact the restriction. Based on what you are describing, I see no functional requirement to maintain the two separate environments. One of the main reasons that separate environments are configurable within Pharos (unlike competing products) is to enable administrators to control the entire user experience as you mentioned (security policies, programs available, proxies/filtering, desktop magnification/contrast for the vision impaired, etc.). Since your environments are identical, there is not a need for both.
You should be able to easily switch one to use the other within the user groups, just remember to do the Change Control. If anything misbehaves or winds up being different after all, the switch back to the original configuration via the drop down is just as easy. Note: There is a chance that the environment is assigned at the computer type level, but since that config seems incongruous with the description of your environment, I did not discuss it.
Pharos Administrator > Users > Groups > Highlight one or more groups in the upper center pane > Change the drop down to the right of Environment in the lower center pane
Thank you Steven, for the clarification. I double checked and the environment for our computer types is "<As per User Group>". So it seems we're good to go. I suspect the two profiles are a holdover from a time when we customized each profile slightly. Such is no longer the case.