So a couple of considerations.
First, ask yourself why you're doing the training you are right now. Because to an extent that's going to dictate how specific you want to try and be with pacing. If you're aiming for structured training with the intent of improving current fitness, then you'll probably want to be more specific. If you're aiming just to go out and have some fun and change things up a bit, then I wouldn't stress about the accuracy of your pacing as much. As long as you complete the workout without a fade and have good form, then you're doing alright.
Second, when it comes to speed work, I'd say ditch the idea of working with your watch when the interval length is 2-3 minutes or less. The shorter the length of time or distance the less accurate the watch will be within that timeframe because it'll have less data points to draw from. That will heavily influence the ability of the watch to do "instant pacing" or recognize "current lap pace" in a fast enough manner for it to be relevant. So my advice is that when the intervals are short like this workout (1 min at 5k pace with goal pace of 8:25), then instead you should figure out the distance you're aiming for and use Google Maps to pre-measure the distance on your normal road route. So let's use these 8:25 min/mile reps of 1 minute. That's 0.118 miles or 191 meters. So I would hop on Google Maps, find a nice stretch of road (ideally flat and straightish with limited road crossings) or track and measure out 191 meters. I prefer trying to find man made objects to use as start and stop points on the route. So like a mailbox or a driveway. Once I have those locations, then when I do the workout, I start my new lap at the mailbox and hit the lap button at the end of the driveway (or wherever the 191m mark is). Then I'll look and see how close I was to 60 seconds. I'd give myself a 1-2 second window (so 58-62 seconds). If I was 55 seconds, then I know I need to slow down on the next one. If I was 65 seconds, then I know I need to speed up on the next one. Anywhere inside my window is completely acceptable. Then I'll make my way back to the start of where the interval is and prepare for the second one. By having the same start and stop, you'll better be able to compare the intervals when they're this short. And you're then only relying on the watch to be able to tell time, not distance. Because you're looking at a start/stop place and the duration it took you to get there. That allows for better comparison and adjustment of effort.
It's not until I get past intervals of 3 minutes or so before I do any checking of pace mid-interval. When it's in that 0-3 min range, I run what feels right and then adjust based on how close each interval was to goal splits. So after the first 7:15 min/mile rep, which would be 0.138 miles or 222 meters, I would say, well I need to slow down on the next one. Conversely if you use the distance based conversion method above, you would have finished your 191 meter rep in 52 seconds. Far far under your 60 second goal and clearly a need to adjust to slower on the next one.
I would be patient though. It's really easy to over-run the effort on a 3 x (4 x 1 minute) 5k workout. As long as the resting intervals were 60 seconds or longer as well, then that's a fairly easy mile based pace workout as well. So I could see how you could over run this and still feel good. It'll obviously start to catch up with you if you tried to maintain that 7:15 mm pace beyond the 2-3 min mark. As that's where you're going to find yourself in a different place physiologically based on your current fitness. But again, if you're consistent with the pace/duration of these and your form is good, then I wouldn't worry too much unless you're trying to be really systematic about your current training. Just make sure that the easy days stay really easy and that'll play a more pivotal role.
single screen with current pace--then it's just a matter of how accurate that live pacing is. Probably need to approach the interval as a ramp up instead of a step-increase in speed.
