THis could explain why SD is different than what we see today as "Shaolin"
During the Sung dynasty, Shaolin also heavily taught long staff routines, partly because they caused less bloodshed than swords, spears and knives. Chan Shi founded the Liu Ho Quan (Six Harmonies Boxing) style based on Shaolin techniques. Also, in 1103AD, a famous general, Yui Fei, brought his soldiers to Shaolin to exchange techniques. He also invented his own forms of boxing, such as Yue San Shou and Yu Chia Quan, Eagle Claw, Nine Way Mandarin Duck Continuous Kicks, among others. It is also during the Sung period that the Xing I (mind boxing) style was invented by combining the Taoist five elements theory with 12 animal-imitating boxing techniques and Shaolin soon taught their own versions of all these routines.
Sometimes during the Sung dynasty, secret societies began to be formed, such as the White Lotus of North and West China. Members began to frequent the Shaolin temple and used its cover for clandestine operations. Such people helped to make martial arts flourish at Shaolin. Many styles of Shaolin-derived boxing were soon developed through Northern China as non-monks who studied at Shaolin left and travelled, sharing what they learned, and developing their own routines and styles (such as Mi-Tsung, Tung Bei, Duan Quan, Duan Dah, and Pao Choi). During the Sung period, Fu Ju, then Abbot of Shaolin, invited experts in 18 martial arts schools to exchange skills with those of Shaolin They stayed three years and wrote the Shaolin Boxing Manual, describing 280 routines (this manual helped Emperor Sun Tai Zu thoroughly master what he had learned at Shaolin).
By the later Sung period, various warlords endangered the countryside and they fought the Sung Emperor for power. In 1279, in the midst of China's inner quarrels, the Mongols invaded China and started the Yuan dynasty, which lasted until 1368AD. To cope with the dangerous times, Shaolin fighting techniques became more of a hard style that primarily used speed, aggressiveness and power, It began to emphasize economy of technique and promoted defence through first strike offence power blows. It was extremely effective for its time, but it was not as subtle as earlier Shaolin Quan. Also, it was not as perfected as later versions of Shaolin Quan; it did not resemble modern Shaolin Kung fu neither in execution nor in philosophy. During the thirteenth century, this type of Shaolin boxing that the monks developed exemplified early kung fu. About 300 forms (170 empty hand and 130 weapons routines) were developed from the original 18 Lohan form. The well-known Shaolin Jin Gang style was developed at this time seeking to preserve the original elements of Shaolin Quan.
After violent nationalist revolts, the Mongols were defeated; Chu Yuan Chan, a Buddhist monk, founded the beloved Ming dynasty, which lasted from 1368-1644AD. During this time, many changes occurred in Shaolin's fighting methods, altering its course for the better. By the Ming dynasty, Shaolin style kung fu was based on techniques embedded in the 18 Lohan styles and forms. But, its execution over the past two centuries had lost its softer, internal properties as it constantly mixed with outsiders and became entwined with military politics. (The Shoalin monks also collected outside styles and routines and taught these there as well). Thus, Shaolin Quan Fa had become less fluid and circular and more rigid and linear, relying on feats of strength and body conditioning for results. It started to be reliant on brute strength, losing its original grace and agility.