Can you update physical and duration % complete at once?

Yes, you can do so, but it may be easier to grasp by doing so in the column view of the activity.

How to update project progress in the P6 web

To determine how a project is performing and what remains to be done, update its progress. Updating a project to reflect the actual work performed to date can be achieved using any of the following methods:

Manually record progress: Record progress for individual activities or resources by entering status data from each member of the team.

Automatically calculate progress: For individual activities, resources, and expenses, use the convenient Auto-Compute Actuals feature to estimate work progress based on the schedule plan. Then, run the Apply Actuals feature. Using these features, the application calculates and applies the expected progress from the previous data date to the new data date you specify. To regularly update a project so that it reflects current actual and remaining values, run the Apply Actuals process using the Scheduled Services page.

What happens when you use the Update Progress feature?

If activities are progressing on schedule, you may want P6 Professional to estimate progress for all activities as of the new data date you specify. P6 Professional can quickly apply actuals to activity dates, and calculate actual duration and units when you use the Update Progress dialog box to update activities.

Estimating activity progress is a quick and convenient way to update your project. P6 Professional estimates progress only for those activities that were supposed to take place. Since progress can occur on activities out of sequence, you may need to update additional activities—especially if you selected activities by dragging the data-date line or by using the Progress Spotlight feature (View, Progress Spotlight). Once you spotlight activities, you can quickly update the project automatically as "on time."

When you use Update Progress to progress activities, P6 Professional will apply actual dates to the activities that should have started and finished, update the actual and remaining durations, and update the remaining units according to the new data date.

how to assign multiple price /units to the same resource...can two budgeted cost columns viewed at the same time....

You can do this in the resources section. You can set two rates either by rate type or by effective dates. Usually you see a resource in one role and using one rate and then at a certain point in time takes on a new role and new rate. The rate type must correspond to the project rate type an only one rate type can be used per project. To clarify, you will have one rate type for the project. The resources that you use will need to have amounts populated in that rate type. You can use different rates for the same resource, but it's best to have them set to be effective at different dates or use an override. As for seing them in budgeted cost, the respective resource rate/costs will roll up to the budgeted costs for the activity. You can see budgeted assignment costs across resources in the assignment view.

I want to update progress for a number of activities.

Use the Progress Spotlight feature (View, Progress Spotlight) to highlight activities in the layout that have started, progressed, or finished between the previous data date and the new data date. If you have the project privileges required to schedule projects, level resources, and apply actuals, you can status the activities that have been highlighted.