No, people are saying that 3x 600m at that intensity in january for a guy running 1.53 is too much, unless you are in Australia and you are peaking in march, even then it is still too early. You should have stopped after the first two anyway as that is specific intensity for someone already running 1.48 for 800m. 3 x 500m would have been more appropriate - I use a progression of 6x300, 4x400, 3x500, 2x600, generally with more recovery if a 4/8 runner. For a less developed runner that progression could be 4x300, 3x400, 2x500, 1x 600. fast reps at Race pace or faster (Lactate Tolerance) need to be handled with care. 200m reps can be used for speed endurance, even 300's if experienced, but volume needs to be controlled in HS.
Check out Purdy tables - 48.5 is level 850. On the sprint side that is 10.8 and 21.8, on the distance side it is 1.51 and 4.12M. I personally take the recoveries with a grain of salt, but for a 48.5 guy it says 2-3 x 600 (4-5min rec) so 90%, should be 1.26. For a HS kid, especially a 4/8 guy (as you claim) I would err on the fewer reps side of the chart. That is intensity for 1-2 reps (95%) 1.22. I consider the first rep (1.21.3) as a time-trial for a 1.48 guy.
For the 1000's it is 4-5 x 1000 (3-4min rec) so 85%, should be 2.49. I think a developed 8/15 guy could do that intensity, but not a 4/8 guy. That is one of the problems I have with the chart, but then I have problems with some of the Daniels's charts as well. Formula's like these are not perfect, they require adjustment.