Let's review some Basics that covers everything you need to know and use:
You can Edit and Set any employee's values right now. Use Excel to update them to Current.
You can Set up the "employee default" to match how new employees start. Then, when you Add an employee, you select how it applies to that person. Example: Everyone starts with 70 hours but not on the hire date. In the Employee Default, this is "beginning of the year." Then, when you add me as a new hire, you see a New Field, for Year Begins On. Set that for my Anniversary date. Since your people already exist, Edit each and fix the data there. New employees are copying the Employee Default for the basic settings that apply; that' why you use it.
You get to set if this is Increased per paycheck, per hour, or pear Year (anniversary date). If anniversary date is only used the First time, then you obviously need to edit and Modify the employees for getting them on track as applies in the second year they work for you, once they get their initial 70 hours populated from the initial setting. The program cannot automate Variable conditions.
I also institute as "use it or be paid for it" at year end. You do that by confirming before year end, for who has time to be paid on the final paycheck of the year. The System won't do this for you. Run reports and monitor this.
Their paystub will not show any time available, if there is no time seen when you Edit the name. In your example, that means all through the first year they work for you = 0.
Any time a person qualifies for the next tier, edit the name and Change the hours and/or the computation, as required to make them on track with their new qualification.