Sometimes, the mash schedule for lager is stepped at different temperatures. The temperatures given in the recipe are before mash gelatinization (144F) and after mash gelatinization (152F). Enzymatic action changes after gelatinization. The writer mentioned a temperature range that works for lager. The recipe might not explain things too well.
It's not a bad idea to learn a little bit about how and why enzymes work and what role they play in making beer.
Brewing lager using the English method and ale malt; interesting recipe. Instead of using the single temp conversion method, why not try step mashing? Mash at 144F for 20 minutes. Then, crank the mash temp up to 149F for 20-30 minutes. Then, a step at 155F for 5 minutes and 158F for 10 minutes. Then, 172F for 10 minutes. Run off the extract. Use boiling water infusions to raise mash temp. The schedule allows the mash to rest longer in the beta range, than in the non-fermentable sugar producing, alpha temp range. Toss in some German Hallertau. Use 34/70 or 830 yeast.
The English method doesn't allow a brewer to have much control over enzymatic action. It's a take what you get method, based on a single temperature conversion. The process might not produce the beer that is expected. Controlling enzymatic action plays a part when it comes to what the final product becomes.